unixdev.net


Switch to SpeakEasy.net DSL

The Modular Manual Browser

Home Page
Manual: (HP-UX-11.11)
Page:
Section:
Apropos / Subsearch:
optional field



 sh-posix(1)                                                     sh-posix(1)




 NAME
      sh, rsh - standard and restricted POSIX.2-conformant command shells

 SYNOPSIS
      sh [{-|+}aefhikmnprstuvx] [{-|+}o option]... [-c string] arg]...

      rsh [{-|+}aefhikmnprstuvx] [{-|+}o option]... [-c string] [arg]...

    Remarks
      This shell is intended to conform to the shell specification of the
      POSIX.2 Shell and Utility standards.  Check any standards conformance
      documents shipped with your system for information on the conformance
      of this shell to any other standards.

    List of Subheadings in DESCRIPTION
      Shell Invocation    Tilde Substitution        Environment
      Options             Command Substitution      Functions
      rsh Restrictions    Parameter Substitution    Jobs
      Definitions         Blank Interpretation      Signals
      Commands            File Name Generation      Execution
      Simple Commands     Quoting                   Command Reentry
      Compound Commands   Arithmetic Evaluation     Command Line Editing
      Special Commands    Prompting                 emacs Editing Mode
      Comments            Conditional Expressions   vi Editing Mode
      Aliasing            Input/Output

 DESCRIPTION
      sh is a command programming language that executes commands read from
      a terminal or a file.

      rsh is a restricted version of sh.  See the "rsh Restrictions"
      subsection below.

    Shell Invocation
      If the shell is invoked by an exec*() system call and the first
      character of argument zero (shell parameter 0) is dash (-), the shell
      is assumed to be a login shell and commands are read first from
      /etc/profile, then from either .profile in the current directory or
      $HOME/.profile if either file exists, and finally from the file named
      by performing parameter substitution on the value of the environment
      parameter ENV, if the file exists.  If the -s option is not present
      and an arg is, a path search is performed on the first arg to
      determine the name of the script to execute.  When running sh with
      arg, the script arg must have read permission and any setuid and
      setgid settings will be ignored.  Commands are read as described
      below.

      Shell output, except for the output of some of the commands listed in
      the "Special Commands" subsection, is written to standard error (file
      descriptor 2).




 Hewlett-Packard Company            - 1 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




    Options
      The following options are interpreted by the shell when it is invoked.

      -c string      Read commands from string.

      -i             If -i is present or if the shell input and output are
                     attached to a terminal (as reported by tty()), the
                     shell is interactive.  In this case SIGTERM is ignored
                     and SIGINT is caught and ignored (so that wait is
                     interruptible).  In all cases, SIGQUIT is ignored by
                     the shell.  See signal(5).

      -r             The shell is a restricted shell.

      -s             If -s is present or if no arguments remain, commands
                     are read from the standard input.

      The remaining options and arguments are described under the set
      command in the "Special Commands" subsection.

    rsh Restrictions
      rsh is used to set up login names and execution environments where
      capabilities are more controlled than those of the standard shell.
      The actions of rsh are identical to those of sh, except that the
      following are forbidden:

           +  Changing directory (see the cd special command and cd(1))
           +  Setting the value of SHELL, ENV, or PATH
           +  Specifying path or command names containing /
           +  Redirecting output (>&gt&gt&gt;, >&gt&gt&gt;|, <&lt&lt&lt;>&gt&gt&gt;, and >&gt&gt&gt;>&gt&gt&gt;)

      The restrictions above are enforced after the .profile and ENV files
      are interpreted.

      When a command to be executed is found to be a shell procedure, rsh
      invokes sh to execute it.  Thus, the end-user is provided with shell
      procedures accessible to the full power of the standard shell, while
      being restricted to a limited menu of commands.  This scheme assumes
      that the end-user does not have write and execute permissions in the
      same directory.

      These rules effectively give the writer of the .profile file complete
      control over user actions, by performing guaranteed set-up actions and
      leaving the user in an appropriate directory (probably not the login
      directory).

      The system administrator often sets up a directory of commands
      (usually /usr/rbin) that can be safely invoked by rsh.  HP-UX systems
      provide a restricted editor red (see ed(1)), suitable for restricted
      users.




 Hewlett-Packard Company            - 2 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




    Definitions
      metacharacter       One of the following characters:

                          ; &&amp&amp&amp; ( ) | <&lt&lt&lt; >&gt&gt&gt; newline space tab

      blank               A tab or a space.

      identifier          A sequence of letters, digits, or underscores
                          starting with a letter or underscore.  Identifiers
                          are used as names for functions and named
                          parameters.

      word                A sequence of characters separated by one or more
                          nonquoted metacharacters.

      command             A sequence of characters in the syntax of the
                          shell language.  The shell reads each command and
                          carries out the desired action, either directly or
                          by invoking separate utilities.

      special command     A command that is carried out by the shell without
                          creating a separate process.  Except for
                          documented side effects, most special commands can
                          be implemented as separate utilities.

      #                   Comment delimiter.  A word beginning with # and
                          all following characters up to a newline are
                          ignored.

      parameter           An identifier, a decimal number, or one of the
                          characters !, #, $, *, -, ?, @, and _.  See the
                          "Parameter Substitution" subsection.

      named parameter     A parameter that can be assigned a value.  See the
                          "Parameter Substitution" subsection.

      variable            A parameter.

      environment variable
                          A parameter that is known outside the local shell,
                          usually by means of the export special command.

    Commands
      A command can be a simple command that executes an executable file, a
      special command that executes within the shell, or a compound command
      that provides flow of control for groups of simple, special, and
      compound commands.

    Simple Commands
      A simple command is a sequence of blank-separated words that may be
      preceded by a parameter assignment list.  (See the "Environment"



 Hewlett-Packard Company            - 3 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




      subsection).  The first word specifies the name of the command to be
      executed.  Except as specified below, the remaining words are passed
      as arguments to the invoked command.  The command name is passed as
      argument 0 (see exec(2)).  The value of a simple-command is its exit
      status if it terminates normally, or 128+errorstatus if it terminates
      abnormally (see signal(5) for a list of errorstatus values).

      A pipeline is a sequence of one or more commands separated by a bar
      (|) and optionally preceded by an exclamation mark (!).  The standard
      output of each command but the last is connected by a pipe (see
      pipe(2)) to the standard input of the next command.  Each command is
      run as a separate process; the shell waits for the last command to
      terminate.  If ! does not precede the pipeline, the exit status of the
      pipeline is the exit status of the last command in the pipeline.
      Otherwise, the exit status of the pipeline is the logical negation of
      the exit status of the last command in the pipeline.

      A list is a sequence of one or more pipelines separated by ;, &&amp&amp&amp;, &&amp&amp&amp;&&amp&amp&amp;,
      or ||, and optionally terminated by ;, &&amp&amp&amp;, or |&&amp&amp&amp;.

           ;    Causes sequential execution of the preceding pipeline.  An
                arbitrary number of newlines can appear in a list, instead
                of semicolons, to delimit commands.

           &&amp&amp&amp;    Causes asynchronous execution of the preceding pipeline
                (that is, the shell does not wait for that pipeline to
                finish).

           |&&amp&amp&amp;   Causes asynchronous execution of the preceding command or
                pipeline with a two-way pipe established to the parent
                shell.  The standard input and output of the spawned command
                can be written to and read from by the parent shell using
                the -p option of the special commands read and print.

           &&amp&amp&amp;&&amp&amp&amp;   Causes the list following it to be executed only if the
                preceding pipeline returns a zero value.

           ||   Causes the list following it to be executed only if the
                preceding pipeline returns a nonzero value.

      Of these five symbols, ;, &&amp&amp&amp;, and |&&amp&amp&amp; have equal precedence, which is
      lower than that of &&amp&amp&amp;&&amp&amp&amp; and ||.  The symbols &&amp&amp&amp;&&amp&amp&amp; and || also have equal
      precedence.

    Compound Commands
      Unless otherwise stated, the value returned by a compound command is
      that of the last simple command executed in the compound command.  The
      ; segment separator can be replaced by one or more newlines.

      The following keywords are recognized only as the first word of a
      command and when not quoted:



 Hewlett-Packard Company            - 4 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




           !            }            elif         for          then
           [[           case         else         function     time
           ]]           do           esac         if           until
           {            done         fi           select       while

      A compound command is one of the following.

      case word in [[;] [(] pattern [| pattern]...) list ;;]... ; esac

           Execute the list associated with the first pattern that matches
           word.  The form of the patterns is identical to that used for
           file name generation (see the "File Name Generation" subsection).
           The ;; case terminator cannot be replaced by newlines.

      for identifier [in word ...] ; do list ; done

           Set identifier to each word in sequence and execute the do list.
           If in word ...  is omitted, set identifier to each set positional
           parameter instead.  See the "Parameter Substitution" subsection.
           Execution ends when there are no more positional parameters or
           words in the list.

      function identifier { list ; }
      identifier () { list ; }

           Define a function named by identifier.  A function is called by
           executing its identifier as a command.  The body of the function
           is the list of commands between { and }.  See the "Functions"
           subsection.

      if list ; then list ; [elif list ; then list ;]... [else list ;] fi

           Execute the if list and, if its exit status is zero, execute the
           first then list.  Otherwise, execute the elif list (if any) and,
           if its exit status is zero, execute the next then list.  Failing
           that, execute the else list (if any).  If no else list or then
           list is executed, if returns a zero exit status.

      select identifier [in word ...] ; do list ; done

           Print the set of words on standard error (file descriptor 2),
           each preceded by a number.  If in word ...  is omitted, print the
           positional parameters instead (see the "Parameter Substitution"
           subsection).  Print the PS3 prompt and read a line from standard
           input into the parameter REPLY.  If this line consists of the
           number of one of the listed words, set identifier to the
           corresponding word, execute list, and repeat the PS3 prompt.  If
           the line is empty, print the selection list again, and repeat the
           PS3 prompt.  Otherwise, set identifier to null, execute list, and
           repeat the PS3 prompt.  The select loop repeats until a break
           special command or end-of-file is encountered.



 Hewlett-Packard Company            - 5 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




      time pipeline

           Execute the pipeline and print the elapsed time, the user time,
           and the system time on standard error.  Note that the time
           keyword can appear anywhere in the pipeline to time the entire
           pipeline. To time a particular command in a pipeline, see
           time(1).

      until list ; do list ; done

           Execute the until list.  If the exit status of the last command
           in the list is nonzero, execute the do list and execute the until
           list again.  When the exit status of the last command in the
           until list is zero, terminate the loop.  If no commands in the do
           list are executed, until returns a zero exit status.

      while list ; do list ; done

           Execute the while list.  If the exit status of the last command
           in the list is zero, execute the do list and execute the while
           list again.  When the exit status of the last command in the
           while list is nonzero, terminate the loop.  If no commands in the
           do list are executed, while returns a nonzero exit status.

      ( list )

           Execute list in a separate environment.  If two adjacent open
           parentheses are needed for nesting, a space must be inserted
           between them to avoid arithmetic evaluation.

      { list ; }

           Execute list, but not in a separate environment.  Note that { is
           a keyword and requires a trailing blank to be recognized.

      [[ expression ]]

           Evaluate expression and return a zero exit status when expression
           is true.  See the "Conditional Expressions" subsection for a
           description of expression.  Note that [[ and ]] are keywords and
           require blanks between them and expression.

    Special Commands
      Special commands are simple commands that are executed in the shell
      process.  They permit input/output redirection.  Unless otherwise
      indicated, file descriptor 1 (standard output) is the default output
      location and the exit status, when there are no syntax errors, is
      zero.

      Commands that are marked with % are treated specially in the following
      ways:



 Hewlett-Packard Company            - 6 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




           1. Variable assignment lists preceding the command remain in
              effect when the command completes.
           2. I/O redirections are processed after variable assignments.
           3. Errors cause a script that contains them to abort.

      Words following commands marked with & that are in the format of a
      variable assignment are expanded with the same rules as a variable
      assignment.  This means that tilde substitution is performed after the
      = sign and word-splitting and file-name generation are not performed.

      % : [arg]...

           (colon)  Only expand parameters.  A zero exit status is returned.

      % . file [arg]...

           (period)  Read and execute commands from file and return.  The
           commands are executed in the current shell environment.  The
           search path specified by PATH is used to find the directory
           containing file.  If any arguments arg are given, they become the
           positional parameters.  Otherwise, the positional parameters are
           unchanged.  The exit status is the exit status of the last
           command executed.

      & alias [-tx] [name[=value]]...

           With name=value specified, define name as an alias and assign it
           the value value.  A trailing space in value causes the next word
           to be checked for alias substitution.

           With name=value omitted, print the list of aliases in the form
           name=value on standard output.

           With name specified without =value, print the specified alias.

           With -t, set tracked aliases.  The value of a tracked alias is
           the full path name corresponding to the given name.  The value of
           a tracked alias becomes undefined when the value of PATH is
           reset, but the alias remains tracked.  With name=value omitted,
           print the list of tracked aliases in the form name=pathname on
           standard output.

           With -x, set exported aliases.  An exported alias is defined
           across subshell environments.  With name=value omitted, print the
           list of exported aliases in the form name=value on standard
           output.

           Alias returns true unless a name is given for which no alias has
           been defined.





 Hewlett-Packard Company            - 7 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




      bg [job]...

           Put the specified jobs into the background.  The current job is
           put in the background if job is unspecified.  See the "Jobs"
           subsection for a description of the format of job.

      % break [n]

           Exit from the enclosing for, select, until, or while loop, if
           any.  If n is specified, exit from n levels.

      cd [-L|-P] [arg]
      cd old new

           In the first form, change the current working directory (PWD) to
           arg.  If arg is -, the directory is changed to the previous
           directory (OLDPWD).

           With -L (default), preserve logical naming when treating symbolic
           links.  cd -L .. moves the current directory one path component
           closer to the root directory.

           With -P, preserve the physical path when treating symbolic links.
           cd -P .. changes the working directory to the actual parent
           directory of the current directory.

           The shell parameter HOME is the default arg.  The parameter PWD
           is set to the current directory.

           The shell parameter CDPATH defines the search path for the
           directory containing arg.  Alternative directory names are
           separated by a colon (:).  If CDPATH is null or undefined, the
           default value is the current directory.  Note that the current
           directory is specified by a null path name, which can appear
           immediately after the equal sign or between the colon delimiters
           anywhere else in the path list.  If arg begins with a /, the
           search path is not used.  Otherwise, each directory in the path
           is searched for arg.  See also cd(1).

           The second form of cd substitutes the string new for the string
           old in the current directory name, PWD, and tries to change to
           this new directory.

      command [arg]...

           Treat arg as a command, but disable function lookup on arg.  See
           command(1) for usage and description.







 Hewlett-Packard Company            - 8 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




      % continue [n]

           Resume the next iteration of the enclosing for, select, until, or
           while loop.  If n is specified, resume at the nth enclosing loop.

      echo [arg]...

           Print arg on standard output.  See echo(1) for usage and
           description.  See also the print special command.

      % eval [arg]...

           Read the arguments as input to the shell and execute the
           resulting commands.  Allows parameter substitution for keywords
           and characters that would otherwise be unrecognized in the
           resulting commands.

      % exec [arg]...

           Parameter assignments remain in effect after the command
           completes.  If arg is given, execute the command specified by the
           arguments in place of this shell without creating a new process.
           Input/output arguments may appear and affect the current process.
           If no arguments are given, modify file descriptors as prescribed
           by the input/output redirection list.  In this case, any file
           descriptor numbers greater than 2 that are opened with this
           mechanism are closed when another program is invoked.

      % exit [n]

           Exit from the shell with the exit status specified by n.  If n is
           omitted, the exit status is that of the last command executed.
           An end-of-file also causes the shell to exit, except when a shell
           has the ignoreeof option set.  (See the set special command.)

      %& export [name[=value]]...
      %& export -p

           Mark the given variable names for automatic export to the
           environment of subsequently executed commands.  Optionally,
           assign values to the variables.

           With -p, write the names and values of all exported variables to
           standard output, in a format with the proper use of quoting, so
           that it is suitable for re-input to the shell as commands that
           achieve the same exporting results.








 Hewlett-Packard Company            - 9 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




      fc [-r] [-e ename] [first [last]]
      fc -l [-nr] [first [last]]
      fc -s [old=new] [first]
      fc -e - [old=new] [command]

           List, or edit and reexecute, commands previously entered to an
           interactive shell.  A range of commands from first to last is
           selected from the last HISTSIZE commands typed at the terminal.
           The arguments first and last can be specified as a number or
           string.  A given string is used to locate the most recent
           command.  A negative number is used to offset the current command
           number.

           With -l, list the commands on standard output.  Without -l,
           invoke the editor program ename on a file containing these
           keyboard commands.  If ename is not supplied, the value of the
           parameter FCEDIT (default /usr/bin/ed) is used as the editor.
           Once editing has ended, the commands (if any) are executed.  If
           last is omitted, only the command specified by first is used.  If
           first is not specified, the default is the previous command for
           editing and -16 for listing.

           With -r, reverse the order of the commands.

           With -n, suppress command numbers when listing.

           With -s, reexecute the command without invoking an editor.

           The old=new argument replaces the first occurrence of string old
           in the command to be reexecuted by the string new.

      fg [job]...

           Bring each job into the foreground in the order specified.  If no
           job is specified, bring the current job into the foreground.  See
           the "Jobs" subsection for a description of the format of job.

      getopts optstring name [arg]...

           Parse the argument list, or the positional parameters if no
           arguments, for valid options.  On each execution, return the next
           option in name.  See getopts(1) for usage and description.

           An option begins with a + or a -.  An argument not beginning with
           + or -, or the argument --, ends the options.  optstring contains
           the letters that getopts recognizes.  If a letter is followed by
           a :, that option is expected to have an argument.  The options
           can be separated from the argument by blanks.

           For an option specified as -letter, name is set to letter.  For
           an option specified as +letter, name is set to +letter.  The



 Hewlett-Packard Company           - 10 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




           index of the next arg is stored in OPTIND.  The option argument,
           if any, is stored in OPTARG.  If no option argument is found, or
           the option found does not take an argument, OPTARG is unset.

           A leading : in optstring causes getopts to store the letter of an
           invalid option in OPTARG, and to set name to ? for an unknown
           option and to : when a required option argument is missing.
           Otherwise, getopts prints an error message.  The exit status is
           nonzero when there are no more options.

      & hash [utility]...
      & hash -r

           Affect the way the current shell environment remembers the
           locations of utilities.  With utility, add utility locations to a
           list of remembered locations.  With no arguments, print the
           contents of the list.  With -r, forget all previously remembered
           utility locations.

      jobs [-lnp] [job]...

           List information about each given job, or all active jobs if job
           is not specified.  With -l, list process IDs in addition to the
           normal information.  With -n, display only jobs that have stopped
           or exited since last notified.  With -p, list only the process
           group.  See the "Jobs" subsection for a description of the format
           of job.

      kill [-s signal] process ...
      kill -l
      kill [-signal] process ...

           Send either signal 15 (SIGTERM, terminate) or the specified
           signal to the specified jobs or processes.  See kill(1) for usage
           and description.

           With -l, list the signal names and numbers.

      let arg ...
      (( arg ...))

           Evaluate each arg as a separate arithmetic expression.  See the
           "Arithmetic Evaluation" subsection for a description of
           arithmetic expression evaluation.  The exit status is 0 if the
           value of the last expression is nonzero, and 1 otherwise.

      % newgrp [-] [group]

           Replace the current shell with a new one having group as the
           user's group.  The default group is the user's login group.  With
           -, the user's .profile and $ENV files are also executed.  See



 Hewlett-Packard Company           - 11 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




           newgrp(1) for usage and description.  Equivalent to
           exec newgrp arg ....

      print [-nprRsu[n]] [arg]...

           The shell output mechanism.  With no options or with option - or
           --, print the arguments on standard output as described in
           echo(1).  See also printf(1).

           With -n, do not add a newline character to the output.

           With -p, write the arguments onto the pipe of the process spawned
           with |&&amp&amp&amp; instead of standard output.

           With -R or -r (raw mode), ignore the escape conventions of echo.
           With -R, print all subsequent arguments and options other than
           -n.

           With -s, write the arguments into the history file instead of to
           standard output.

           With -u, specify a one-digit file descriptor unit number n on
           which the output will be placed.  The default is 1 (standard
           output).

      pwd [-L|-P]

           Print the name of the current working directory (equivalent to
           print -r - $PWD).  With -L (the default), preserve the logical
           meaning of the current directory.  With -P, preserve the physical
           meaning of the current directory if it is a symbolic link.  See
           also the cd special command, cd(1), ln(1), and pwd(1).

      read [-prsu[n]] [name?prompt] [name]...

           The shell input mechanism.  Read one line (by default, from
           standard input) and break it up into words using the characters
           in IFS as separators.  The first word is assigned to the first
           name, the second word to the second name, and so on; the
           remaining words are assigned to the last name.  See also read(1).
           The return code is 0, unless an end-of-file is encountered.

           With -p, take the input line from the input pipe of a process
           spawned by the shell using |&&amp&amp&amp;.  An end-of-file with -p causes
           cleanup for this process so that another process can be spawned.

           With -r (raw mode), a \ at the end of a line does not signify
           line continuation.

           With -s, save the input as a command in the history file.




 Hewlett-Packard Company           - 12 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




           With -u, specify a one-digit file descriptor unit to read from.
           The file descriptor can be opened with the exec special command.
           The default value of n is 0 (standard input).  If name is
           omitted, REPLY is used as the default name.

           If the first argument contains a ?, the remainder of the argument
           is used as a prompt when the shell is interactive.

           If the given file descriptor is open for writing and is a
           terminal device, the prompt is placed on that unit.  Otherwise,
           the prompt is issued on file descriptor 2 (standard error).

      %& readonly [name[=value]]...
      %& readonly -p

           Mark the given names read only.  These names cannot be changed by
           subsequent assignment.

           With -p, write the names and values of all read-only variables to
           standard output in a format with the proper use of quoting so
           that it is suitable for re-input to the shell as commands that
           achieve the same attribute-setting results.

      % return [n]

           Cause a shell function to return to the invoking script with the
           return status specified by n.  If n is omitted, the return status
           is that of the last command executed.  Only the low 8 bits of n
           (decimal 0 to 255) are passed back to the caller.  If return is
           invoked while not in a function or a . script (see the . special
           command), it has the same effect as an exit command.

      % set [{-|+}abCefhkmnopstuvx] [{-|+}o option]... [{-|+}A
      name] [arg]...

           Set (-) or clear (+) execution options or perform array
           assignments (-A, +A).  All options except -A and +A can be
           supplied in a shell invocation (see the SYNOPSIS section and the
           "Shell Invocation" subsection).

           Using + instead of - before an option causes the option to be
           turned off.  These options can also be used when invoking the
           shell.  The current list of set single-letter options is
           contained in the shell variable -.  It can be examined with the
           command echo $-.

           The - and + options can be intermixed in the same command, except
           that there can be only one -A or +A option.

           Unless -A or +A is specified, the remaining arg arguments are
           assigned consecutively to the positional parameters 1, 2, ....



 Hewlett-Packard Company           - 13 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




           The set command with neither arguments nor options displays the
           names and values of all shell parameters on standard output.  See
           also env(1).

           The options are defined as follows.

           -A   Array assignment.  Unset the variable name and assign values
                sequentially from the list arg.  With +A, do not unset the
                variable name first.

           -a   Automatically export subsequently defined parameters.

           -b   Cause the shell to notify the user asynchronously of
                background jobs as they are completed.  When the shell
                notifies the user that a job has been completed, it can
                remove the job's process ID from the list of those known in
                the current shell execution environment.

           -C   Prevent redirection >&gt&gt&gt; from truncating existing files.
                Requires >&gt&gt&gt;| to truncate a file when turned on.

           -e   Execute the ERR trap, if set, and exit if a command has a
                nonzero exit status, and is not part of the compound list
                following a if, until, or while keyword, and is not part of
                an AND or OR list, and is not a pipeline preceded by the !
                reserved word.  This mode is disabled while reading
                profiles.

           -f   Disable file name generation.

           -h   Specify that each command whose name is an identifier
                becomes a tracked alias when first encountered.

           -k   Place all parameter assignment arguments (not just those
                that precede the command name) into the environment for a
                command.

           -m   Run background jobs in a separate process group and print a
                line upon completion.  The exit status of background jobs is
                reported in a completion message.  This option is turned on
                automatically for interactive shells.

           -n   Read commands and check them for syntax errors, but do not
                execute them.  The -n option is ignored for interactive
                shells.

           -o   Set an option argument from the following list.  Repeat the
                -o option to specify additional option arguments.

                allexport      Same as -a.




 Hewlett-Packard Company           - 14 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




                bgnice         Run all background jobs at a lower priority.
                errexit        Same as -e.
                emacs          Use a emacs-style inline editor for command
                               entry.
                gmacs          Use a gmacs-style inline editor for command
                               entry.
                ignoreeof      Do not exit from the shell on end-of-file
                               (eof as defined by stty; default is ^D).  The
                               exit special command must be used.
                keyword        Same as -k.
                markdirs       Append a trailing / to all directory names
                               resulting from file name generation.
                monitor        Same as -m.
                noclobber      Same as -C.
                noexec         Same as -n.
                noglob         Same as -f.
                nolog          Do not save function definitions in history
                               file.
                notify         Same as -b.
                nounset        Same as -u.
                privileged     Same as -p.
                verbose        Same as -v.
                trackall       Same as -h.
                vi             Use a vi-style inline editor for command
                               entry.
                viraw          Process each character as it is typed in vi
                               mode (always on).
                xtrace         Same as -x.

           -p   Disable processing of the $HOME/.profile file and uses the
                file /etc/suid_profile instead of the ENV file.  This mode
                is on whenever the effective user ID (group ID) is not equal
                to the real user ID (group ID).  Turning this off causes the
                effective user ID and group ID to be set to the real user ID
                and group ID.

           -s   Sort the positional parameters.

           -t   Exit after reading and executing one command.

           -u   Treat unset parameters as an error when substituting.

           -v   Print shell input lines as they are read.

           -x   Print commands and their arguments as they are executed.

           -    Turn off -x and -v options and stop examining arguments for
                options.

           --   Do not change any of the options; useful in setting
                parameter 1 to a value beginning with -.  If no arguments



 Hewlett-Packard Company           - 15 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




                follow this option, the positional parameters are unset.

      % shift [n]

           Rename the positional parameters from n+1 ... to 1 ....  The
           default value of n is 1.  n can be any arithmetic expression that
           evaluates to a nonnegative number less than or equal to $#.

      test [expr]

           Evaluate conditional expression expr.  See test(1) for usage and
           description.  The arithmetic comparison operators are not
           restricted to integers.  They allow any arithmetic expression.
           The following additional primitive expressions are allowed:

                -L file             True if file is a symbolic link.
                -e file             True if file exists.
                file1 -nt file2     True if file1 is newer than file2.
                file1 -ot file2     True if file1 is older than file2.
                file1 -ef file2     True if file1 has the same device and
                                    i-node number as file2.

      % times

           Print the accumulated user and system times for the shell and for
           processes run from the shell.

      % trap [arg] [sig]...

           Set arg as a command that is read and executed when the shell
           receives a sig signal.  (Note that arg is scanned once when the
           trap is set and once when the trap is taken.) Each sig can be
           given as the number or name of a signal.  Letter case is ignored.
           For example, 3, QUIT, quit, and SIGQUIT all specify the same
           signal.  Use kill -l to get a list of signals.

           Trap commands are executed in signal number order.  Any attempt
           to set a trap on a signal that was ignored upon entering the
           current shell is ineffective.  Traps remain in effect for a given
           shell until explicitly changed with another trap command; that
           is, a trap set within a function will remain in effect even after
           the function returns.

           If arg is - (or if arg is omitted and the first sig is numeric),
           reset all traps for each sig to their original values.

           If arg is the null string ('' or ""), each sig is ignored by the
           shell and by the commands it invokes.

           If sig is DEBUG, then arg is executed after each command.  If sig
           is ERR, arg is executed whenever a command has a nonzero exit



 Hewlett-Packard Company           - 16 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




           code.  If sig is 0 or EXIT, the command arg is executed on exit
           from the shell.

           With no arguments, print a list of commands associated with each
           signal name.

      & typeset [{-|+}LRZfilrtux[n]] [name[=value]]...
      name=value [name=value]...

           Assign types and a value to a local named parameter name.  See
           also the export special command.  Parameter assignments remain in
           effect after the command completes.  When invoked inside a
           function, create a new instance of the parameter name.  The
           parameter value and type are restored when the function
           completes.

           The following list of attributes can be specified.  Use + instead
           of - to turn the options off.

           -L   Left justify and remove leading blanks from value.  If n is
                nonzero, it defines the width of the field; otherwise, it is
                determined by the width of the value of first assignment.
                When name is assigned, the value is filled on the right with
                blanks or truncated, if necessary, to fit into the field.
                Leading zeros are removed if the -Z option is also set.  The
                -R option is turned off.  Flagged as leftjust n.

           -R   Right justify and fill with leading blanks.  If n is
                nonzero, it defines the width of the field; otherwise, it is
                determined by the width of the value of first assignment.
                The field is left-filled with blanks or truncated from the
                end if the parameter is reassigned.  The -L option is turned
                off.  Flagged as rightjust n.

           -Z   Right justify and fill with leading zeros if the first
                nonblank character is a digit and the -L option has not been
                set.  If n is nonzero it defines the width of the field;
                otherwise, it is determined by the width of the value of
                first assignment.  Flagged as zerofill n plus the flag for
                -L or -R.

           -f   Cause name to refer to function names rather than parameter
                names.  No assignments can be made to the name declared with
                the typeset statement.  The only other valid options are -t
                (which turns on execution tracing for this function) and -x
                (which allows the function to remain in effect across shell
                procedures executed in the same process environment).
                Flagged as function.

           -i   Parameter is an integer.  This makes arithmetic faster.  If
                n is nonzero it defines the output arithmetic base;



 Hewlett-Packard Company           - 17 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




                otherwise, the first assignment determines the output base.
                Flagged as integer [base n].

           -l   Convert all uppercase characters to lowercase.  The
                uppercase -u option is turned off.  Flagged as lowercase.

           -r   Mark any given name as "read only".  The name cannot be
                changed by subsequent assignment.  Flagged as readonly.

           -t   Tag the named parameters.  Tags are user-definable and have
                no special meaning to the shell.  Flagged as tagged.

           -u   Convert all lowercase characters to uppercase characters.
                The lowercase -l option is turned off.  Flagged as
                uppercase.

           -x   Mark any given name for automatic export to the environment
                of subsequently executed commands.  Flagged as export.

           typeset alone displays a list of parameter names, prefixed by any
           flags specified above.

           typeset - displays the parameter names followed by their values.
           Specify one or more of the option letters to restrict the list.
           Some options are incompatible with others.

           typeset + displays the parameter names alone.  Specify one or
           more of the option letters to restrict the list.  Some options
           are incompatible with others.

      ulimit [-HSacdfnst] [limit]

           Set or display a resource limit.  The limit for a specified
           resource is set when limit is specified.  The value of limit can
           be a number in the unit specified with each resource, or the
           keyword unlimited.

           The -H and -S flags specify whether the hard limit or the soft
           limit is set for the given resource.  A hard limit cannot be
           increased once it is set.  A soft limit can be increased up to
           the hard limit.  If neither -H nor -S is specified, the limit
           applies to both.  The current resource limit is printed when
           limit is omitted.  In this case, the soft limit is printed unless
           -H is specified.  When more than one resource is specified, the
           limit name and unit are printed before the value.

           If no option is given, -f is assumed.

                -a   List all of the current resource limits.
                -c   The number of 512-byte blocks in the size of core
                     dumps.



 Hewlett-Packard Company           - 18 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




                -d   The number of kilobytes in the size of the data area.
                -f   The number of 512-byte blocks in files written by child
                     processes (files of any size can be read).
                -n   The number of file descriptors.
                -s   The number of kilobytes in the size of the stack area.
                -t   The number of seconds to be used by each process.

      umask [-S] [mask]

           Set the user file-creation mask mask.  mask can be either an
           octal number or a symbolic value as described in umask(1).  A
           symbolic value shows permissions that are unmasked.  An octal
           value shows permissions that are masked off.

           Without mask, print the current value of the mask.  With -S,
           print the value in symbolic format.  Without -S, print the value
           as an octal number.  The output from either form can be used as
           the mask of a subsequent invocation of umask.

      unalias name ...
      unalias -a

           Remove each name from the alias list.  With -a, remove all alias
           definitions from the current shell execution environment.

      % unset [-fv] name ...

           Remove the named shell parameters from the parameter list.  Their
           values and attributes are erased.  Read-only variables cannot be
           unset.  With -f, names refer to function names.  With -v, names
           refer to variable names.  Unsetting _, ERRNO, LINENO, MAILCHECK,
           OPTARG, OPTIND, RANDOM, SECONDS, and TMOUT removes their special
           meaning, even if they are subsequently assigned to.

      wait [job]

           Wait for the specified job to terminate or stop, and report its
           status.  This status becomes the return code for the wait
           command.  Without job, wait for all currently active child
           processes to terminate or stop.  The termination status returned
           is that of the last process.  See the "Jobs" subsection for a
           description of the format of job.

      whence [-pv] name ...

           For each name, indicate how it would be interpreted if used as a
           command name.  With -v, produce a more verbose report.  With -p
           do a path search for name, disregarding any use as an alias, a
           function, or a reserved word.





 Hewlett-Packard Company           - 19 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




    Comments
      A word beginning with # causes that word and all the following
      characters up to a newline to be ignored.

    Aliasing
      The first word of each command is replaced by the text of an alias, if
      an alias for this word has been defined.  An alias name consists of
      any number of characters excluding metacharacters, quoting characters,
      file expansion characters, parameter and command substitution
      characters, and =.  The replacement string can contain any valid shell
      script, including the metacharacters listed above.  The first word of
      each command in the replaced text, other than any that are in the
      process of being replaced, will be tested for additional aliases.  If
      the last character of the alias value is a blank, the word following
      the alias is also checked for alias substitution.  Aliases can be used
      to redefine special commands, but cannot be used to redefine the
      keywords listed in the "Compound Commands" subsection.  Aliases can be
      created, listed, and exported with the alias command and can be
      removed with the unalias command.  Exported aliases remain in effect
      for subshells but must be reinitialized for separate invocations of
      the shell (see the "Shell Invocation" subsection).

      Aliasing is performed when scripts are read, not while they are
      executed.  Therefore, for it to take effect, an alias must be executed
      before the command referring to the alias is read.

      Aliases are frequently used as a shorthand for full path names.  An
      option to the aliasing facility allows the value of the alias to be
      automatically set to the full path name of the corresponding command.
      These aliases are called tracked aliases.  The value of a tracked
      alias is defined the first time the identifier is read and becomes
      undefined each time the PATH variable is reset.  These aliases remain
      tracked so that the next reference will redefine the value.  Several
      tracked aliases are compiled into the shell.  The -h option of the set
      command converts each command name that is an identifier into a
      tracked alias.

      The following exported aliases are compiled into the shell but can be
      unset or redefined:

           autoload='typeset -fu'
           command='command '
           functions='typeset -f'
           history='fc -l'
           integer='typeset -i'
           local=typeset
           nohup='nohup '
           r='fc -e -'
           stop='kill -STOP'
           suspend='kill -STOP $$'
           type='whence -v'



 Hewlett-Packard Company           - 20 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




    Tilde Substitution
      After alias substitution is performed, each word is checked to see if
      it begins with an unquoted tilde (~).  If it does, the word up to a /
      is checked to see if it matches a user name in the /etc/passwd file.
      If a match is found, the ~ and the matched login name are replaced by
      the login directory of the matched user.  If no match is found, the
      original text is left unchanged.  A ~ alone or before a / is replaced
      by the value of the HOME parameter.  A ~ followed by a + or - is
      replaced by the value of the parameter PWD and OLDPWD, respectively.
      In addition, tilde substitution is attempted when the value of a
      parameter assignment begins with a ~.

    Command Substitution
      The standard output from a command enclosed in parenthesis preceded by
      a dollar sign ($(...)) or a pair of grave accents (`...`) can be used
      as part or all of a word; trailing newlines are removed.  In the
      second (archaic) form, the string between the accents is processed for
      special quoting characters before the command is executed.  See the
      "Quoting" subsection.  The command substitution $(cat file) can be
      replaced by the equivalent but faster $(<&lt&lt&lt;file).  Command substitution
      of most special commands that do not perform input/output redirection
      are carried out without creating a separate process.

      An arithmetic expression enclosed in double parenthesis preceded by a
      dollar sign ($((...))) is replaced by the value of the arithmetic
      expression within the double parenthesis.  See the "Arithmetic
      Evaluation" subsection for a description of arithmetic expressions.

    Parameter Substitution
      A parameter is an identifier, one or more decimal digits, or one of
      the characters !, #, $, *, -, ?, @, and _.  A named parameter (a
      parameter denoted by an identifier) has a value and zero or more
      attributes.  Named parameters can be assigned values and attributes
      with the typeset special command.  Exported parameters pass values and
      attributes to the environment.

      The shell supports a limited one-dimensional array facility.  An
      element of an array parameter is referenced by a subscript.  A
      subscript is denoted by a [, followed by an arithmetic expression,
      followed by a ].  See the "Arithmetic Evaluation" subsection.  To
      assign values to an array, use set -A name value ....  The value of
      all subscripts must be in the range of 0 through 1023.  Arrays need
      not be declared.  Any reference to a named parameter with a valid
      subscript is legal and an array is created if necessary.  Referencing
      an array parameter without a subscript is equivalent to referencing
      the first element.

      If the -i integer attribute is set for name, the value is subject to
      arithmetic evaluation.





 Hewlett-Packard Company           - 21 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




      Positional parameters, parameters denoted by a number, can be assigned
      values with the set special command.  Parameter 0 is set from argument
      zero when the shell is invoked.

      Use the prefix character $ to specify the value of a parameter for
      substitution.

      $parameter
      ${parameter}
      ${parameter[subscript]}
                     Substitute the value of the parameter, if any.  Braces
                     are required when parameter is followed by a letter,
                     digit, or underscore that should not be interpreted as
                     part of its name or when a named parameter is
                     subscripted.  If parameter is one or more digits, it is
                     a positional parameter.  A positional parameter of more
                     than one digit must be enclosed in braces.  The shell
                     reads all the characters from ${ to the matching } as
                     part of the same word, even if it contains braces or
                     metacharacters.

                     If parameter is * or @, all the positional parameters,
                     starting with 1, are substituted (separated by a field
                     separator character).  See the "Quoting" subsection.

                     If an array parameter with subscript * or @ is used,
                     the value for each element is substituted (separated by
                     a field separator character).

      ${#parameter}  If parameter is * or @, the number of positional
                     parameters is substituted.  Otherwise, the length of
                     the value of the parameter is substituted.

      ${#parameter[*]}
                     Substitute the number of elements in the array.

      ${parameter:-word}
                     If parameter is set and is nonnull, substitute its
                     value; otherwise, substitute word.

      ${parameter:=word}
                     If parameter is not set or is null, set it to word;
                     then substitute the value of the parameter.  Positional
                     parameters may not be assigned in this way.

      ${parameter:?word}
                     If parameter is set and is nonnull, substitute its
                     value; otherwise, print word and exit from the shell.
                     If word is omitted, a standard message is printed.





 Hewlett-Packard Company           - 22 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




      ${parameter:+word}
                     If parameter is set and is nonnull, substitute word;
                     otherwise, substitute nothing.

      ${parameter#pattern}
      ${parameter##pattern}
                     If the shell pattern matches the beginning of the value
                     of parameter, the value of this substitution is the
                     value of the parameter with the matched portion
                     deleted; otherwise, the value of this parameter is
                     substituted.  In the former case, the smallest matching
                     pattern is deleted; in the latter case, the largest
                     matching pattern is deleted. These characters # or %
                     should be escaped by a backslash (\) or quotes ('').

      ${parameter%pattern}
      ${parameter%%pattern}
                     If the shell pattern matches the end of the value of
                     parameter, the value of parameter with the matched part
                     is deleted; otherwise, substitute the value of
                     parameter.  In the former, the smallest matching
                     pattern is deleted; in the latter, the largest matching
                     pattern is deleted. These characters # or % should be
                     escaped by a backslash (\) or quotes ('').

      In the above, word is not evaluated unless it is used as the
      substituted string.  Thus, in the following example, pwd is executed
      only if d is not set or is null:

           echo  ${d:-$(pwd)}

      If the colon (:) is omitted from the above expressions, the shell only
      checks to determine whether or not parameter is set.

      + The following parameters are set automatically by the shell:

      0              The string used to call the command or script, set from
                     invocation argument zero.

      1, 2, ...      The positional parameters.

      *, @           All the set positional parameters, separated by a field
                     separator character.  See the "Quoting" subsection.

      #              The number of set positional parameters in decimal.

      -              Flags supplied to the shell on invocation or by the set
                     command.

      ?              The decimal exit status returned by the last executed
                     command.



 Hewlett-Packard Company           - 23 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




      $              The process number of this shell.

      _              Initially, the absolute path name of the shell or
                     script being executed, as passed in the environment.
                     Subsequently, it is assigned the last argument of the
                     previous command.  This parameter is not set for
                     commands which are asynchronous.  This parameter is
                     also used to hold the name of the matching MAIL file
                     when checking for mail.

      !              The process number of the last background command
                     invoked.

      ERRNO          The value of errno as set by the most recently failed
                     system call.  This value is system-dependent and is
                     intended for debugging purposes.

      LINENO         The line number of the current line within the script
                     or function being executed.

      OLDPWD         The previous working directory set by the cd command.

      OPTARG         The value of the last option argument processed by the
                     getopts special command.

      OPTERR         If set to 0, OPTERR will suppress error messages from
                     the getopts special command.  OPTERR is initially set
                     to 1.

      OPTIND         The index of the last option argument processed by the
                     getopts special command.

      PPID           The process number of the parent of the shell.

      PWD            The present working directory set by the cd command.

      RANDOM         Each time this parameter is evaluated, a random
                     integer, uniformly distributed between 0 and 32767, is
                     generated.  The sequence of random numbers can be
                     initialized by assigning a numeric value to RANDOM.

      REPLY          Set by the select compound command, and by the read
                     special command when no name is supplied.

      SECONDS        Each time this parameter is referenced, the number of
                     seconds since shell invocation is returned.  If this
                     parameter is assigned a value, the value returned upon
                     reference is the value that was assigned plus the
                     number of seconds since the assignment.





 Hewlett-Packard Company           - 24 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




      + The following parameters are used by the shell:

      CDPATH         The search path for the cd command, a list of
                     directories separated by colons.

      COLUMNS        If this variable is set, its value is used to define
                     the width of the edit window for the shell edit modes
                     and for printing select lists.

      EDITOR         If the value of this variable ends in emacs, gmacs, or
                     vi and the VISUAL variable is not set, the
                     corresponding option is turned on (see the set special
                     command.

      ENV            If this parameter is set, parameter substitution is
                     performed on the value to generate the path name of the
                     script to be executed when the shell is invoked (see
                     the "Invocation" subsection).  This file is typically
                     used for alias and function definitions.

      FCEDIT         The default editor name for the fc command.

      FPATH          The search path for function definitions, a list of
                     directories separated by colons.  This path is searched
                     when a function with the -u attribute is referenced and
                     when a command is not found.  If an executable file is
                     found, then it is read and executed in the current
                     environment.

      IFS            Internal field separators, normally space, tab, and
                     newline, that are used to separate command words
                     resulting from command or parameter substitution and
                     for separating words with the special command read.
                     The first character of the IFS parameter is used to
                     separate arguments for the $* substitution (see the
                     "Quoting" subsection).  If the value of IFS is space,
                     tab, and newline, or if IFS is unset and it is being
                     used to separate the results of command or parameter
                     substitution, any sequence of IFS characters serves to
                     delimit words; otherwise, each occurrence of a
                     character in IFS serves to delimit a word.  If the
                     value of IFS is null, no word splitting is done.

      HISTFILE       If this parameter is set when the shell is invoked, its
                     value is the path name of the file that is used to
                     store the command history.  The default value is
                     $HOME/.sh_history.  If the user is a superuser and no
                     HISTFILE is given, then no history file is used.  See
                     the "Command Reentry" subsection and the WARNINGS
                     section.




 Hewlett-Packard Company           - 25 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




      HISTSIZE       If this parameter is set when the shell is invoked, the
                     number of previously entered commands accessible to
                     this shell will be greater than or equal to this
                     number.  The default is 128.

      HOME           The default argument (home directory) for the cd
                     command.

      LANG           The locale of your system, which is made up of three
                     parts: language, territory, and code set.  The default
                     is the C locale.  See environ(5).

      LC_ALL         The overriding value for LANG and the LC_* variables.
                     See environ(5).

      LC_COLLATE     The collating sequence to use when sorting names and
                     when character ranges occur in patterns.  See
                     environ(5).

      LC_CTYPE       The character classification information to use.
                     Changing the value of LC_CTYPE after the shell has
                     started does not affect the lexical processing of shell
                     commands in the current shell execution environment or
                     its subshells.  See environ(5).

      LC_MESSAGES    The language in which system messages appear, and the
                     language that the system expects for user input of yes
                     and no strings.  See environ(5).

      LC_MONETARY    The currency symbol and monetary value format.  See
                     environ(5).

      LC_NUMERIC     The numeric format.  See environ(5).

      LC_TIME        The date and time format.  See environ(5).

      LINES          If this variable is set, the value is used to determine
                     the column length for printing select lists.  select
                     lists print vertically until about two-thirds of LINES
                     lines are filled.

      MAIL           If this parameter is set to the name of a mail file and
                     the MAILPATH parameter is not set, the shell informs
                     the user of arrival of mail in the specified file.

      MAILCHECK      How often (in seconds) the shell checks for changes in
                     the modification time of any of the files specified by
                     the MAILPATH or MAIL parameters.  The default value is
                     600 seconds.  When the time has elapsed, the shell
                     checks before issuing the next prompt.




 Hewlett-Packard Company           - 26 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




      MAILPATH       A list of file names separated by colons.  If this
                     parameter is set, the shell informs the user of any
                     modifications to the specified files that have occurred
                     within the last MAILCHECK seconds.  Each file name can
                     be followed by a ?  and a message to be printed, in
                     which case the message will undergo parameter and
                     command substitution with the parameter $_ defined as
                     the name of the changed file.  The default message is
                     you have mail in $_.

      NLSPATH        The search path for message catalogs, a list of
                     directories separated by colons.

      PATH           The search path for commands, a list of directories
                     separated by colons.  See the "Execution" subsection.

      PS1            The value of this parameter is expanded for parameter
                     substitution, to define the primary prompt string.  The
                     default value is "$ ".  The character ! in the primary
                     prompt string is replaced by the command number.  See
                     the "Command Reentry" subsection.

      PS2            Secondary prompt string for command completion.  The
                     default value is ">&gt&gt&gt; ".

      PS3            Selection prompt string used within a select loop.  If
                     unset, it defaults to "#? ".

      PS4            Execution trace string that precedes each line of an
                     execution trace.  See the set -x special command.  If
                     unset, it defaults to "+ ".

      SHELL          The path name of the shell is kept in the environment.
                     When invoked, the shell is restricted if the value of
                     this variable contains an r in the base name.

      TMOUT          If set to a value greater than zero, the shell will
                     terminate if a command is not entered within the
                     prescribed number of seconds after issuing the PS1
                     prompt.  (Note that the shell can be compiled with a
                     maximum bound for this value which cannot be exceeded.)

      VISUAL         Invokes the corresponding option when the value of this
                     variable ends in emacs, gmacs, or vi.  See the set -o
                     special command.

      The shell gives default values to IFS, MAILCHECK, PATH, PS1, PS2, and
      TMOUT.  On the other hand, MAIL, ENV, HOME, and SHELL are never set
      automatically by the shell (although HOME, MAIL, and SHELL are set by
      login; see login(1)).




 Hewlett-Packard Company           - 27 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




    Blank Interpretation
      After parameter and command substitution, the results of substitution
      are scanned for field separator characters (defined in IFS), and split
      into distinct arguments when such characters are found.  sh retains
      explicit null arguments ("" or '') but removes implicit null arguments
      (those resulting from parameters that have null values).

    File Name Generation
      Following substitution, each command word is processed as a pattern
      for file name expansion unless expansion has been disabled with the
      set -f special command.  The form of the patterns is the Pattern
      Matching Notation defined in regexp(5).  The word is replaced with
      sorted file names matching the pattern.  If no file name is found that
      matches the pattern, the word is left unchanged.

      In addition to the notation described in regexp(5), sh recognizes
      composite patterns made up of one or more pattern lists separated from
      each other with a |.  Composite patterns can be formed with one or
      more of the following:

           ?(pattern-list)   Matches any one of the given patterns.
           *(pattern-list)   Matches zero or more occurrences of the given
                             patterns.
           +(pattern-list)   Matches one or more occurrences of the given
                             patterns.
           @(pattern-list)   Matches exactly one of the given patterns.
           !(pattern-list)   Matches anything, except one of the given
                             patterns.

    Quoting
      Each of the metacharacters (see the "Definitions" subsection) has a
      special meaning to the shell and terminates a word unless quoted.  A
      character may be quoted (that is, made to stand for itself) by
      preceding it with a backslash (\).  The pair \newline is ignored; the
      current and following lines are concatenated.

      All characters enclosed between a pair of apostrophes ('...') are
      quoted.  An apostrophe cannot appear within apostrophes.

      Parameter and command substitution occurs inside quotation marks
      ("...").  \ quotes the characters \, `, ", and $.

      Inside grave accent marks (`...`), \ quotes the characters \, `, and
      $.  If the grave accents occur within quotation marks, \ also quotes
      the character ".

      The meanings of $* and $@ are identical when not quoted or when used
      as a parameter assignment value or as a file name.  However, when used
      as a command argument, "$*" is equivalent to "$1d$2d...", whereas "$@"
      is equivalent to "$1"d"$2"d... (where d is the first character of
      IFS),



 Hewlett-Packard Company           - 28 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




      The special meaning of keywords or aliases can be removed by quoting
      any character of the name.  The recognition of function names or
      special command names cannot be altered by quoting them.

    Arithmetic Evaluation
      Integer arithmetic is provided with the special command let.
      Evaluations are performed using long integer arithmetic.  Constants
      take the form base#n or n, where base is a decimal number between two
      and thirty-six representing the arithmetic base and n is a number in
      that base.  If base# is omitted, base 10 is used.

      An arithmetic expression uses the same syntax, precedence, and
      associativity of expression as the C language.  All the integral
      operators, other than ++, --, ?:, and , are supported.  Variables can
      be referenced by name within an arithmetic expression without using
      the parameter substitution syntax.  When a variable is referenced, its
      value is evaluated as an arithmetic expression.

      A variable can be typed as an integer with the -i option of the
      typeset special command, as in typeset -i[base] name.  Arithmetic
      evaluation is performed on the value of each assignment to a variable
      with the -i attribute.  If you do not specify an arithmetic base, the
      first assignment to the variable determines the arithmetic base.  This
      base is used when parameter substitution occurs.

      Since many of the arithmetic operators require quoting, an alternative
      form of the let command is provided.  For any command beginning with
      ((, all characters until the matching )) are treated as a quoted
      expression.  More precisely, ((...)) is equivalent to let "...".

    Prompting
      When used interactively, the shell prompts with the value of PS1
      before reading a command.  Whenever a newline is received and further
      input is needed to complete a command, the secondary prompt (the value
      of PS2) is issued.

    Conditional Expressions
      A conditional expression is used with the [[ compound command to test
      attributes of files and to compare strings.  Word splitting and file
      name generation are not performed on the words between [[ and ]].
      Each expression can be constructed from one or more of the following
      unary or binary expressions:

           -a file             True, if file exists.
           -b file             True, if file exists and is a block special
                               file.
           -c file             True, if file exists and is a character
                               special file.
           -d file             True, if file exists and is a directory.
           -e file             True, if file exists.




 Hewlett-Packard Company           - 29 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




           -f file             True, if file exists and is an ordinary file.
           -g file             True, if file exists and has its setgid bit
                               set.
           -h file             True, if file exists and is a symbolic link.
           -k file             True, if file exists and has its sticky bit
                               set.
           -n string           True, if length of string is nonzero.
           -o option           True, if the set option named option is on.
           -p file             True, if file exists and is a fifo special
                               file or a pipe.
           -r file             True, if file exists and is readable by
                               current process.
           -s file             True, if file exists and has a size greater
                               than zero.
           -t fildes           True, if file descriptor number fildes is
                               open and is associated with a terminal
                               device.
           -u file             True, if file exists and has its setuid bit
                               set.
           -w file             True, if file exists and is writable by the
                               current process.
           -x file             True, if file exists and is executable by the
                               current process.  If file exists and is a
                               directory, then the current process has
                               permission to search in the directory.
           -z string           True, if length of string is zero.
           -L file             True, if file exists and is a symbolic link.
           -O file             True, if file exists and is owned by the
                               effective user ID of this process.
           -G file             True, if file exists and its group matches
                               the effective group ID of this process.
           -S file             True, if file exists and is a socket.
           file1 -nt file2     True, if file1 exists and is newer than
                               file2.
           file1 -ot file2     True, if file1 exists and is older than
                               file2.
           file1 -ef file2     True, if file1 and file2 exist and refer to
                               the same file.
           string = pattern    True, if string matches pattern.
           string != pattern   True, if string does not match pattern.
           string <&lt&lt&lt; string2    True, if string1 comes before string2 based
                               on the ASCII value of their characters.
           string >&gt&gt&gt; string2    True, if string1 comes after string2 based on
                               the ASCII value of their characters.
           exp1 -eq exp2       True, if exp1 is equal to exp2.
           exp1 -ne exp2       True, if exp1 is not equal to exp2.
           exp1 -lt exp2       True, if exp1 is less than exp2.
           exp1 -gt exp2       True, if exp1 is greater than exp2.
           exp1 -le exp2       True, if exp1 is less than or equal to exp2.
           exp1 -ge exp2       True, if exp1 is greater than or equal to
                               exp2.



 Hewlett-Packard Company           - 30 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




      A compound expression can be constructed from these primitives by
      using any of the following, listed in decreasing order of precedence.

           (exp)               True, if exp is true.  Used to group
                               expressions.
           !exp                True, if exp is false.
           exp1 &&amp&amp&amp;&&amp&amp&amp; exp2        True, if exp1 and exp2 are both true.
           exp1 || exp2        True, if either exp1 or exp2 is true.

    Input/Output
      Before a command is executed, its input and output can be redirected
      using a special notation interpreted by the shell.  The following can
      appear anywhere in a simple-command or may precede or follow a command
      and are not passed on to the invoked command.  Command and parameter
      substitution occurs before word or digit is used, except as noted
      below.  File name generation occurs only if the pattern matches a
      single file and blank interpretation is not performed.

           <&lt&lt&lt;word          Use file word as standard input (file descriptor
                          0).

           >&gt&gt&gt;word          Use file word as standard output (file descriptor
                          1).  If the file does not exist, it is created.
                          If the file exists, and the noclobber option is
                          on, an error occurs; otherwise, the file is
                          truncated to zero length.

           >&gt&gt&gt;|word         Same as >&gt&gt&gt;, except that it overrides the noclobber
                          option.

           >&gt&gt&gt;>&gt&gt&gt;word         Use file word as standard output.  If the file
                          exists, output is appended to it (by first
                          searching for the end-of-file); otherwise, the
                          file is created.

           <&lt&lt&lt;>&gt&gt&gt;word         Open file word for reading and writing as standard
                          input.

           <&lt&lt&lt;<&lt&lt&lt;[-]word      The shell input is read up to a line that matches
                          word, or to an end-of-file.  No parameter
                          substitution, command substitution or file name
                          generation is performed on word.  The resulting
                          document, called a here-document, becomes the
                          standard input.  If any character of word is
                          quoted, no interpretation is placed upon the
                          characters of the document.  Otherwise, parameter
                          and command substitution occurs, \newline is
                          ignored, and \ must be used to quote the
                          characters \, $, `, and the first character of
                          word.  If - is appended to <&lt&lt&lt;<&lt&lt&lt;, all leading tabs
                          are stripped from word and from the document.



 Hewlett-Packard Company           - 31 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




           <&lt&lt&lt;&&amp&amp&amp;digit        The standard input is duplicated from file
                          descriptor digit (see dup(2)).

           >&gt&gt&gt;&&amp&amp&amp;digit        The standard output is duplicated to file
                          descriptor digit (see dup(2)).

           <&lt&lt&lt;&&amp&amp&amp;-            The standard input is closed.

           >&gt&gt&gt;&&amp&amp&amp;-            The standard output is closed.

           <&lt&lt&lt;&&amp&amp&amp;p            The input from the coprocess is moved to standard
                          input.

           >&gt&gt&gt;&&amp&amp&amp;p            The output to the coprocess is moved to standard
                          output.

      If any of the above redirections is preceded by a digit (0 to 9), the
      file descriptor used is the one specified by the digit, instead of the
      default 0 (standard input) or 1 (standard output).  For example:

           2>&gt&gt&gt;&&amp&amp&amp;1

      means open file descriptor 2 for writing as a duplicate of file
      descriptor 1.  Output directed to file descriptor 2 is written in the
      same location as output to file descriptor 1.

      Order is significant in redirection.  The shell evaluates each
      redirection in terms of the (file descriptor, file) assignment at the
      time of evaluation.  For example:

           1>&gt&gt&gt;fname 2>&gt&gt&gt;&&amp&amp&amp;1

      first assigns file descriptor 1 to file fname.  It then assigns file
      descriptor 2 to the file assigned to file descriptor 1 (that is,
      fname).

      If the order of redirection is reversed, as in

           2>&gt&gt&gt;&&amp&amp&amp;1 1>&gt&gt&gt;fname

      file descriptor 2 is assigned to the file assigned to file descriptor
      1 (probably the terminal) and then file descriptor 1 is assigned to
      file fname.

      By using the redirection operators above, the input and output of a
      coprocess may be moved to a numbered file descriptor, allowing other
      commands to write to them and read from them.  If the input of the
      current coprocess is moved to a numbered file descriptor, another
      coprocess may be started.





 Hewlett-Packard Company           - 32 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




      If a command is followed by &&amp&amp&amp; and job control is inactive, the default
      standard input for the command is the empty file /dev/null.
      Otherwise, the environment for the execution of a command contains the
      file descriptors of the invoking shell as modified by input/output
      specifications.

    Environment
      The environment (see environ(5)) is a list of name-value pairs passed
      to an executed program much like a normal argument list.  The names
      must be identifiers and the values are character strings.  The shell
      interacts with the environment in several ways.  When invoked, the
      shell scans the environment and creates a parameter for each name
      found, gives it the corresponding value and marks it export.  Executed
      commands inherit the environment.  If the user modifies the values of
      these parameters or creates new ones by using the export or typeset -x
      special commands, the values become part of the environment.  The
      environment seen by any executed command is thus composed of any
      name-value pairs originally inherited by the shell, whose values may
      be modified by the current shell, plus any additions which must be
      noted in export or typeset -x commands.

      The environment for any simple command or function can be augmented by
      prefixing it with one or more parameter assignments.  A parameter
      assignment argument takes the form identifier=value.  For example,
      both the following

           TERM=450 cmd args
           (export TERM; TERM=450; cmd args)

      are equivalent (as far as the execution of cmd is concerned, except
      for the special commands that are preceded by a percent sign (%).

      If the -k option is set, all parameter assignment arguments are placed
      in the environment, even if they occur after the command name.  The
      following echo statement prints a=b c.  After the -k option is set,
      the second echo statement prints only c:

           echo a=b c -> a=b c
           set -k
           echo a=b c -> c

      This feature is intended for use with scripts written for early
      versions of the shell and its use in new scripts is strongly
      discouraged.  It is likely to disappear someday.

    Functions
      The function command (described in the "Compound Commands" subsection)
      defines shell functions.  Shell functions are read and stored
      internally.  Alias names are resolved when the function is read.
      Functions are executed like commands, with the arguments passed as
      positional parameters.  (See the "Execution" subsection.)



 Hewlett-Packard Company           - 33 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




      Functions execute in the same process as the caller and share all
      files and current working directory with the caller.  Traps defined by
      the caller remain in effect within the function until another trap
      command is executed.  Traps set within a function remain in effect
      after the function returns.  Ordinarily, variables are shared between
      the calling program and the function.  However, the typeset special
      command can be used within a function to define local variables whose
      scope includes the current function and all functions it calls.

      The return special command is used to return from function calls.
      Errors within functions return control to the caller.

      Function identifiers can be listed with the +f option of the typeset
      special command.  Function identifiers and the associated text of the
      functions can be listed with the -f option.  Functions can be
      undefined with the -f option of the unset special command.

      Ordinarily, functions are unset when the shell executes a shell
      script.  The -xf option of the typeset command allows a function to be
      exported to scripts that are executed without reinvoking the shell.
      Functions that must be defined across separate invocations of the
      shell should be placed in the ENV file.

    Jobs
      If the monitor option of the set command is turned on, an interactive
      shell associates a job with each pipeline.  It keeps a table of
      current jobs, printed by the jobs command, and assigns them small
      integer numbers.  When a job is started asynchronously with &&amp&amp&amp;, the
      shell prints a line that looks like:

           [1] 1234

      indicating that job number 1 was started asynchronously and had one
      (top-level) process whose process ID was 1234.

      If you are running a job and wish to do something else, you can type
      the suspend character (the susp character defined with stty; see
      stty(1)) to send a SIGSTOP signal to the current job.  The shell then
      indicates that the job has been Stopped, and prints another prompt.
      Then you can manipulate the state of this job by putting it in the
      background with the bg command, running other commands, and eventually
      returning the job to the foreground with the fg command.  A suspend
      takes effect immediately and resembles an interrupt, since pending
      output and unread input are discarded when the suspend is entered.

      A job running in the background stops if it tries to read from the
      terminal.  Background jobs normally are allowed to produce output, but
      can be disabled with the stty tostop command.  If the user sets this
      terminal option, background jobs stop when trying to produce output.





 Hewlett-Packard Company           - 34 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




      There are several ways to refer to jobs in the shell.  A job can be
      referred to by the process ID of any process in the job or by one of
      the following:

           %number             The job with the given number.
           %string             Any job whose command line begins with
                               string.
           %?string            Any job whose command line contains string.
           %%                  Current job.
           %+                  Equivalent to %%.
           %-                  Previous job.

      The shell learns immediately when a process changes state.  It informs
      the user when a job is blocked and prevented from further progress,
      but only just before it prints a prompt.

      When the monitor mode is on, each background job that completes
      triggers any trap set for SIGCHLD.

      If you try to exit from shell while jobs are stopped, you are warned
      with the message You have stopped jobs.  You can use the jobs command
      to identify them.  If you immediately try to exit again, the shell
      will not warn you a second time, and the stopped jobs will be
      terminated.

      If you try to leave the shell while jobs are running, you are not
      warned.  The shell exits silently and sets the parent of the running
      jobs to the init process (number 1).

    Signals
      The SIGINT and SIGQUIT signals for an invoked command are ignored if
      the command is followed by &&amp&amp&amp; and the monitor option is off.
      Otherwise, signals have the values inherited by the shell from its
      parent, with the exception of signal SIGSEGV (but see also the trap
      special command).

    Execution
      Substitutions are made each time a command is executed.  sh checks the
      command name to determine whether it matches a special command.  If it
      does, it is executed within the current shell process.

      Next, sh checks the command name to determine whether it matches one
      of the user-defined functions.  If it does, sh saves the positional
      parameters, then sets them to the arguments of the function call.  The
      positional parameter 0 is unchanged.  When the function completes or
      issues a return, sh restores the positional parameter list.  The value
      of a function is the value of the last command executed.  A function
      is executed in the current shell process.

      If a command name is not a user-defined function or a special command,
      sh creates a process and attempts to execute the command using an



 Hewlett-Packard Company           - 35 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




      exec*() system call (see exec(2)).

      The shell parameter PATH defines the search path for the directory
      containing the command.  Alternative directory names are separated by
      a colon (:).  The default path is /usr/bin: (specifying /usr/bin, and
      the current directory, in that order).  Note that the current
      directory is specified by a null path name, which can appear
      immediately after the equal sign, between colon delimiters, or at the
      end of the path list.  The search path is not used if the command name
      contains a /.  Otherwise, each directory in the path is searched for
      an executable file.  If the file has execute permissions but is not a
      directory or an executable object code file, it is assumed to be a
      script file, which is a file of data for an interpreter.  If the first
      two characters of the script file are #!, exec*() expects an
      interpreter path name to follow.  exec*() then attempts to execute the
      specified interpreter as a separate process to read the entire script
      file.  If a call to exec*() fails, sh is spawned to interpret the
      script file.  All nonexported aliases, functions, and named parameters
      are removed in this case.  If the shell command file does not have
      read permission, or if the setuid and/or setgid bits are set on the
      file, the shell executes an agent to set up the permissions and
      execute the shell with the shell command file passed down as an open
      file.  A parenthesized command is also executed in a subshell without
      removing nonexported quantities.

    Command Reentry
      The text of the last HISTSIZE (default 128) commands entered from a
      terminal device is saved in a history file.  The file
      $HOME/.sh_history is used if the HISTFILE variable is not set or
      writable.  A shell can access the commands of all interactive shells
      that use the same named HISTFILE.  The special command fc is used to
      list or edit a portion of this file.  The portion of the file to be
      edited or listed can be selected by number or by giving the first
      character or characters of the command.  A single command or range of
      commands can be specified.  If you do not specify an editor program as
      an argument to fc, the value of the parameter FCEDIT is used.  If
      FCEDIT is not defined, /usr/bin/ed is used.  The edited command is
      printed and reexecuted upon leaving the editor.  The editor name - is
      used to skip the editing phase and to reexecute the command.  In this
      case, a substitution parameter of the form old=new can be used to
      modify the command before execution.  For example, if r is aliased to
      fc -e -, typing r bad=good c reexecutes the most recent command that
      starts with the letter c and replaces the first occurrence of the
      string bad with the string good.

      The history file will be trimmed when all of the following conditions
      occurs:

           Its size is greater than four kilobytes.





 Hewlett-Packard Company           - 36 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




           The number of commands in it is more than HISTSIZE.

           The file has not been modified in the last ten minutes.

           The user has write permission for the directory in which the
           history file resides.

      If any one of the above conditions does not occur, the history file
      will not be trimmed. When the history file is trimmed, the latest
      HISTSIZE commands will be available in the history file.

    Command Line Editing
      Normally, each command line typed at a terminal device is followed by
      a newline or return.  If one of the emacs, gmacs, vi, or viraw,
      options is set, you can edit the command line.  An editing option is
      automatically selected each time the VISUAL or EDITOR variable is
      assigned a value ending in one of these option names.

      The editing features require that the user's terminal accept return
      without line feed and that a space (" ") must overwrite the current
      character on the screen.  ADM terminal users should set the
      "space - advance" switch to "space".  Hewlett-Packard terminal users
      should set the straps to "bcGHxZ etX".

      The editing modes enable the user to look through a window at the
      current line.  The default window width is 80, unless the value of
      COLUMNS is defined.  If the line is longer than the window width minus
      two, a mark displayed at the end of the window notifies the user.  The
      mark is one of:

           >&gt&gt&gt;    The line extends to the right.
           <&lt&lt&lt;    The line extends to the left.
           *    The line extends to both sides of the window.

      As the cursor moves and reaches the window boundaries, the window is
      centered about the cursor.

      The search commands in each edit mode provide access to the history
      file.  Only strings are matched, not patterns, although a leading ^ in
      the string restricts the match to begin at the first character in the
      line.

    emacs Editing Mode
      This mode is invoked by either the emacs or gmacs option.  Their sole
      difference is their handling of ^T.  To edit, the user moves the
      cursor to the point needing correction and inserts or deletes
      characters or words.  All editing commands are control characters or
      escape sequences.  The notation for control characters is caret (^)
      followed by a character.  For example, ^F is the notation for
      Control-F.  This is entered by holding down the Ctrl (control) key and
      pressing f.  The shift key is not pressed.  The notation ^? indicates



 Hewlett-Packard Company           - 37 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




      the delete (DEL) key.

      The notation for escape sequences is M- followed by a character.  For
      example, M-f (pronounced meta f) is entered by pressing the escape key
      (ESC) followed by pressing f.  M-F is the notation for escape followed
      by shift (capital) F.

      All edit commands operate from any place on the line (not only at the
      beginning).  Neither the return (^M) nor the newline (^J) key is
      entered after edit commands, except when noted.

           ^F             Move cursor forward (right) one character.
           M-f            Move cursor forward one word.  (The editor's idea
                          of a word is a string of characters consisting of
                          only letters, digits and underscores.)
           ^B             Move cursor backward (left) one character.
           M-b            Move cursor backward one word.
           ^A             Move cursor to start of line.
           ^E             Move cursor to end of line.
           ^]char         Move cursor forward to character char on current
                          line.
           M-^]char       Move cursor backward to character char on current
                          line.
           ^X^X           Interchange the cursor and mark.
           erase          Delete previous character.  (User-defined erase
                          character as defined by the stty command, usually
                          ^H or #.)
           ^D             Delete current character.
           eof            Terminate the shell if the current line is null.
                          (User-defined end-of-file character as defined by
                          the stty command, usually ^D.)
           M-d            Delete current word.
           M-^H           Delete previous word.  (meta-backspace)
           M-h            Delete previous word.
           M-^?           Delete previous word. (meta-delete) If your
                          interrupt character is ^? (DEL, the default), this
                          command will not work.
           ^T             In emacs mode, transpose current character with
                          next character.  In gmacs mode, transpose two
                          previous characters.
           ^C             Capitalize current character.
           M-c            Capitalize current word.
           M-l            Change the current word to lowercase.
           ^K             Delete from the cursor to the end of the line.  If
                          preceded by a numerical parameter whose value is
                          less that the current cursor position, then delete
                          from the given position up to the cursor.  If
                          preceded by a numerical parameter whose value is
                          greater than the current cursor position, then
                          delete from the cursor up to the given position.




 Hewlett-Packard Company           - 38 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




           ^W             Kill from the cursor to the mark.
           M-p            Push the region from the cursor to the mark on the
                          stack.
           kill           Kill the entire current line.  If two kill
                          characters are entered in succession, all
                          subsequent consecutive kill characters cause a
                          line feed (useful when using paper terminals).
                          (User-defined kill character as defined by the
                          stty command, usually ^X or @.)
           ^Y             Restore last item removed from line.  (Yank item
                          back to the line.)
           ^L             Line feed and print current line.
           ^@             Set mark.  (null character)
           M-             Set mark.  (meta-space)
           ^J             Execute the current line.  (newline)
           ^M             Execute the current line.  (return)
           ^P             Fetch previous command.  Each time ^P is entered,
                          the previous command in the history list is
                          accessed.
           ^N             Fetch next command.  Each time ^N is entered the
                          next command in the history list is accessed.
           M-<&lt&lt&lt;            Fetch the least recent (oldest) history line.
           M->&gt&gt&gt;            Fetch the most recent (youngest) history line.
           ^Rstring       Reverse search history for a previous command line
                          containing string.  If a parameter of zero is
                          given, the search is forward.  string is
                          terminated by a return or newline.  If string is
                          preceded by a ^, the matched line must begin with
                          string.  If string is omitted, the next command
                          line containing the most recent string is
                          accessed.  In this case, a parameter of zero
                          reverses the direction of the search.
           ^O             Execute the current line and fetch the next line
                          relative to current line from the history file.
           M-digits       Define a numeric parameter.  The digits are taken
                          as a parameter to the next command.  The commands
                          that accept a parameter are erase, ^B, ^C, ^D, ^F,
                          ^K, ^N, ^P, ^R, ^], M-^H, M-., M-_, M-b, M-c, M-d,
                          M-f, M-h, and M-l.
           M-letter       Your alias list is searched for an alias by the
                          name _letter (underscore-letter).  If an alias of
                          this name is defined, its value is inserted on the
                          input queue.  This letter must not be one of the
                          above metafunctions.
           M-.            The last word of the previous command is inserted
                          on the line.  If preceded by a numeric parameter,
                          the value of this parameter determines which word
                          to insert rather than the last word.
           M-_            Same as M-..
           M-*            Attempt file name generation on the current word.




 Hewlett-Packard Company           - 39 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




           M-^[           File name completion.  (meta-escape.) Replaces the
                          current word with the longest common prefix of all
                          file names matching the current word with an
                          asterisk appended.  If the match is unique, a / is
                          appended if the file is a directory and a space is
                          appended if the file is not a directory.
           M-=            List files matching current word pattern as if an
                          asterisk were appended.
           ^U             Multiply parameter of next command by 4.
           \              Escape next character.  Editing characters and
                          your erase, kill, and interrupt characters may be
                          entered in a command line or in a search string,
                          if preceded by a \.  The \ removes the next
                          character's editing features (if any).
           ^V             Display version of the shell.
           M-#            Insert a # at the beginning of the line and
                          execute it.  This causes a comment to be inserted
                          in the history file.

    vi Editing Mode
      The editor starts in insert mode until an escape (ESC) is received.
      This puts you in control mode in which you can move the cursor and
      perform editing commands.  A return in either mode sends the line.

      Most control commands accept an optional repeat count prior to the
      command.

      In vi mode on most systems, canonical processing is initially enabled
      and the command is echoed again if the speed is 1200 baud or greater
      and contains any control characters, or if less than one second has
      elapsed since the prompt was printed.  The escape (ESC) character
      terminates canonical processing for the remainder of the command and
      you can then modify the command line.  This scheme has the advantages
      of canonical processing with the typeahead echoing of raw mode.

      Setting the viraw option always disables canonical processing on the
      terminal.  This mode is implicit for systems that do not support two
      alternate end-of-line delimiters, and may be helpful for certain
      terminals.

      Insert Edit Commands
      By default, the editor is in insert mode.

           erase          Delete previous inserted character.  The erase
                          character is user-definable with the stty command,
                          usually set to ^H.  The system default is #.
           kill           Delete all current inserted characters.  The kill
                          character is user-definable with the stty command,
                          usually set to ^X or ^U.  The system default is @.
           \              Escape the next erase or kill character.




 Hewlett-Packard Company           - 40 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




           ^D             Terminate the shell.
           ^V             Escape next character.  Editing characters and
                          erase or kill characters may be entered in a
                          command line or in a search string if preceded by
                          a ^V, which removes the next character's editing
                          features (if any).
           ^W             Delete the previous blank-separated word.

      Motion Edit Commands
      These commands move the cursor.  The use of count causes a repetition
      of the command the cited number of times.

           [count]l       Cursor forward (right) one character.
           [count]w       Cursor forward one alphanumeric word.
           [count]W       Cursor forward to the beginning of the next word
                          that follows a blank.
           [count]e       Cursor forward to the end of the word.
           [count]E       Cursor forward to end of the current blank-
                          delimited word.
           [count]h       Cursor backward (left) one character.
           [count]b       Cursor backward one word.
           [count]B       Cursor backward to preceding blank-separated word.
           [count]|       Cursor to column count.  Default is 1.
           [count]fc      Find the next character c in the current line.
           [count]Fc      Find the previous character c in the current line.
           [count]tc      Equivalent to fc followed by h.
           [count]Tc      Equivalent to Fc followed by l.
           [count];       Repeat the last single-character find command, f,
                          F, t, or T.
           [count],       Reverses the last single character find command.
           0              Cursor to start of line.
           ^              Cursor to first nonblank character in line.
           $              Cursor to end of line.

      History Search Commands
      These commands access your command history file.

           [count]k       Fetch previous command.  Each time k is entered,
                          the next earlier command in the history list is
                          accessed.
           [count]-       Equivalent to k.
           [count]j       Fetch next command.  Each time j is entered, the
                          next later command in the history list is
                          accessed.
           [count]+       Equivalent to j.
           [count]G       The command number count is fetched.  The default
                          is the first command in the history list.
           /string        Search backward through history for a previous
                          command containing string.  string is terminated
                          by a return or newline.  If string is preceded by
                          a ^, the matched line must begin with string.  If



 Hewlett-Packard Company           - 41 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




                          string is null, the previous string is used.
           ?string        Same as /, but search in the forward direction.
           n              Search for next match of the last pattern to the /
                          or ?  commands.
           N              Search for next match of the last pattern to / or
                          ?, but in reverse direction.

      Text Modification Edit Commands
      These commands will modify the line.

           a              Enter insert mode after the current character.
           A              Append text to the end of the line.  Equivalent to
                          $a.
           [count]cmotion
           c[count]motion Move cursor forward to the character position
                          specified by motion, deleting all characters
                          between the original cursor position and the new
                          position, and enter insert mode.  If motion is c,
                          the entire line is deleted.
           C              Delete from the current character through the end
                          of line and enter insert mode.  Equivalent to c$.
           S              Equivalent to cc.
           [count]dmotion
           d[count]motion Move cursor to the character position specified by
                          motion, deleting all characters between the
                          original cursor position and the new position.  If
                          motion is d, the entire line will be deleted.
           D              Delete from the current character through the end
                          of line.  Equivalent to d$.
           i              Enter insert mode before the current character.
           I              Enter insert mode before the beginning of the
                          line.  Equivalent to the two-character sequence
                          0i.
           [count]P       Insert the previous text modification before the
                          cursor.
           [count]p       Insert the previous text modification after the
                          cursor.
           R              Enter insert mode and replace characters on the
                          screen with characters you type, overlay fashion.
           [count]rc      Replace the current character with c.
           [count]x       Delete the current character.
           [count]X       Delete the preceding character.
           [count].       Repeat the previous text modification command.
           ~              Invert the case of the current character and
                          advance the cursor.
           [count]_       Append the count word of the previous command at
                          the current cursor location and enter insert mode
                          at the end of the appended text.  The last word is
                          used if count is omitted.
           *              Append an * to the current word and attempt file
                          name generation.  If no match is found, ring the



 Hewlett-Packard Company           - 42 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




                          bell.  If a match is found, replace the word with
                          the matching string of file names and enter insert
                          mode.
           escape
           \              Attempt file name completion on the current word.
                          Replace the current word with the longest common
                          prefix of all file names matching the current word
                          with an asterisk appended.  If the match is
                          unique, append a / if the file is a directory or
                          append a space if the file is not a directory.

      Other Edit Commands

           [count]ymotion
           y[count]motion Yank current character through character that
                          motion would move the cursor to and put them into
                          the delete buffer.  The text and cursor are
                          unchanged.
           Y              Yank from current position to end of line.
                          Equivalent to y$.
           u              Undo the last text-modifying command.
           U              Undo all the text-modifying commands performed on
                          the line.
           [count]v       Execute the command fc -e ${VISUAL:-${EDITOR:-vi}}
                          count in the input buffer.  If count is omitted,
                          the current line is used.  This executes an editor
                          with the current line as the input "file".  When
                          you exit from the editor, the result is executed.
           ^L             Line feed and print current line.
           ^J             Execute the current line, regardless of mode.
                          (newline)
           ^M             Execute the current line, regardless of mode.
                          (return)
           #              Insert a # at the beginning of the current line
                          and after each embedded newline, and execute the
                          line.  Useful for inserting the current command
                          line in the history list without executing it.
           =              List the file names that match the current word if
                          an asterisk were appended to it.
           @letter        Search your alias list for an alias with the name
                          _letter (underscore letter).  If an alias of this
                          name is defined, its value is executed as a
                          command sequence on the current line.  This
                          provides a simple macro capability.

 EXTERNAL INFLUENCES
    Environment Variables
      LC_COLLATE determines the collating sequence used in evaluating
      pattern matching notation for file name generation.  If it is not
      defined or is empty, it defaults to the value of LANG.




 Hewlett-Packard Company           - 43 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




      LC_CTYPE determines the classification of characters as letters, and
      the characters matched by character class expressions in pattern
      matching notation.  If it is not defined or is empty, it defaults to
      the value of LANG.

      If LANG is not defined or is empty, it defaults to C (see lang(5)).

      If any internationalization variable contains an invalid value, they
      all default to C (see environ(5)).

    International Code Set Support
      Single- and multibyte character code sets are supported.

 RETURN VALUE
      Errors detected by the shell, such as syntax errors, cause the shell
      to return a nonzero exit status.  Otherwise, the shell returns the
      exit status of the last command executed.  See also the exit special
      command.  If the shell is being used noninteractively, the execution
      of the shell file is abandoned.  Runtime errors detected by the shell
      are reported by printing the command or function name and the error
      condition.  If the line number on which the error occurred is greater
      than one, the line number is also printed in brackets ([]) after the
      command or function name.

 WARNINGS
      Some file descriptors are used internally by the POSIX shell.  For
      HP-UX releases 10.10 and beyond, file descriptors 24 through 30 are
      reserved.  HP-UX releases 10.00 and 10.01 reserve descriptors 54
      through 60.  Applications using these and forking a subshell should
      not depend upon them surviving in the subshell or its descendants.

      If a command that is a tracked alias is executed, and a command with
      the same name is installed in a directory in the search path before
      the directory where the original command was found, the shell will
      continue to load and execute the original command.  Use the -t option
      of the alias command to correct this situation.

      If you move the current directory or one above it, pwd may not give
      the correct response.  Use the cd command with a full path name to
      correct this situation.

      Some very old shell scripts use a caret (^) as a synonym for the pipe
      character (|).  sh does not recognize the caret as a pipe character.

      If a command is piped into a shell command, all variables set in the
      shell command are lost when the command completes.

      Using the fc built-in command within a compound command will cause the
      entire command to disappear from the history file.





 Hewlett-Packard Company           - 44 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




      The dot (.) special command, as in . file, reads the entire file
      before any commands are executed.  Therefore, alias and unalias
      commands in the file will not apply to any functions defined in the
      file.

      Traps are not processed while the shell is waiting for a foreground
      job.  Thus, a trap on SIGCHLD is not executed until the foreground job
      terminates.

      The export special command does not handle arrays properly.  Only the
      first element of an array is exported to the environment.

      Background processes started from a noninteractive shell cannot be
      accessed with job control commands.

      The value of the IFS variable in the user's environment affects the
      behavior of scripts.

    Collating Order
      In an international environment, character ordering is determined by
      the value of LC_COLLATE, rather than by the binary ordering of
      character values in the machine collating sequence.  This brings with
      it certain attendant dangers, particularly when using range
      expressions in file name generation patterns.  For example, the
      command,

           rm [a-z]*

      might be expected to match all file names beginning with a lowercase
      alphabetic character.  However, if dictionary ordering is specified by
      LC_COLLATE, it would also match file names beginning with an uppercase
      character (as well as those beginning with accented letters).
      Conversely, it would fail to match letters collated after z in
      languages such as Danish or Norwegian.

      The correct (and safe) way to match specific character classes in an
      international environment is to use a pattern (see regexp(5)) of the
      form:

           rm [[:lower:]]*

      This uses LC_CTYPE to determine character classes and works
      predictably for all supported languages and codesets.  For shell
      scripts produced on noninternationalized systems (or without
      consideration for the above dangers), it is recommended that they be
      executed in a non-NLS environment.  This requires that LANG,
      LC_COLLATE, and so on, be set to C or not set at all.

      The history file does not support mixing of locales in the same file.
      For users of multiple locales, you can assign a unique history file
      for each locale by setting HISTFILE as:



 Hewlett-Packard Company           - 45 -   HP-UX Release 11i: November 2000






 sh-posix(1)                                                     sh-posix(1)




           HISTFILE=$HOME/.sh_hist_${LANG}

 AUTHOR
      sh was developed by AT&T, OSF, and HP.

 FILES
      $HOME/.profile                Read to set up user's custom environment
      /etc/passwd                   To find home directories
      /etc/profile                  Read to set up system environment
      /etc/suid_profile             Security profile
      /var/tmp/sh*                  For here-documents if /var/tmp is
                                    accessible
      /tmp/sh*                      For here-documents if /var/tmp is not
                                    accessible
      /usr/bin/sh                   Shell executable program location

 SEE ALSO
      cat(1), cd(1), command(1), echo(1), ed(1), env(1), getopts(1),
      kill(1), ln(1), login(1), newgrp(1), printf(1), pwd(1), read(1),
      stty(1), test(1), time(1), umask(1), vi(1), dup(2), exec(2), fork(2),
      pipe(2), stty(2), ulimit(2), umask(2), wait(2), rand(3C), a.out(4),
      profile(4), environ(5), lang(5), regexp(5), signal(5).

 STANDARDS CONFORMANCE
      sh: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2

      .: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2
      :: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2
      break: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2
      case: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2
      continue: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2
      eval: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2
      exec: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2
      exit: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2
      export: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2
      for: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2
      if: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2
      read: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2
      return: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2
      set: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2
      shift: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2
      time: SVID2, SVID3, XPG2, XPG3, XPG4
      trap: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2
      unset: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2
      until: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2
      while: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2








 Hewlett-Packard Company           - 46 -   HP-UX Release 11i: November 2000