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XARGS(1V)                                                            XARGS(1V)



NAME
       xargs - construct the arguments list(s) and execute a command

SYNOPSIS
       xargs  [  -ptx ] [ -eeofstr ] [ -ireplstr ] [ -lnumber ] [ -nnumber ] [
       -ssize ] [ command [initial-arguments ] ]

AVAILABILITY
       This command is available  with  the  System  V  software  installation
       option.  Refer to for information on how to install optional software.

DESCRIPTION
       xargs combines the fixed initial-arguments with arguments read from the
       standard input, to execute the specified command  one  or  more  times.
       The  number of arguments read for each command invocation, and the man-
       ner in which they are combined are determined by the options specified.

       command, which may be a shell file, is searched for using one's  $PATH.
       If command is omitted, /usr/bin/echo is used.

       Arguments  read in from the standard input are defined to be contiguous
       strings of characters delimited by white space.  Empty lines are always
       discarded.   Blanks  and tabs may be embedded as part of an argument if
       they are escaped or quoted.  Characters enclosed in quotes  (single  or
       double)  are  taken  literally,  and the delimiting quotes are removed.
       Outside of quoted strings, a `\' (backslash) will escape the  character
       it precedes.

       Each arguments-list is constructed starting with the initial-arguments,
       followed by some number of  arguments  read  from  the  standard  input
       (Exception:  see  the -i option).  Options -i, -l, and -n determine how
       arguments are selected for each command invocation.  When none of these
       options are coded, the initial-arguments are followed by arguments read
       continuously from the standard input until an internal buffer is  full,
       and  then  command  is  executed  with the accumulated arguments.  This
       process is repeated until there are none left.  When there  are  option
       conflicts  (for  instance,  -l versus -n), the last option takes prece-
       dence.

       xargs will terminate if it receives a return code of -1, or if it  can-
       not execute command.  When command is a shell script, it should explic-
       itly exit (see sh(1)) with an appropriate value to  avoid  accidentally
       returning with -1.

OPTIONS
       -p             Prompt  mode.  The user is asked whether to execute com-
                      mand each invocation.  Trace mode (-t) is turned  on  to
                      print the command instance to be executed, followed by a
                      ?...  prompt.  A reply of y (optionally followed by any-
                      thing)  will execute the command; anything else, includ-
                      ing just a return, skips that particular  invocation  of
                      command.

       -t             Trace  mode.   The command and each constructed argument
                      list are echoed to file descriptor 2 just prior to their
                      execution.

       -x             Terminate  xargs  if  any argument list would be greater
                      than size characters; -x is forced by the options -i and
                      -l.   When  neither  of  the  options  -i, -l, or -n are
                      coded, the total length of all arguments must be  within
                      the size limit.

       -eeofstr       eofstr  is taken as the logical EOF string.  `_' (under-
                      bar) is assumed for the logical EOF string if -e is  not
                      coded.   The value -e with no eofstr coded turns off the
                      logical EOF string capability (underbar is taken  liter-
                      ally).   xargs reads the standard input until either EOF
                      or the logical EOF string is encountered.

       -ireplstr      Insert mode: command is executed for each line from  the
                      standard input, taking the entire line as a single argu-
                      ment, inserting it in initial-arguments for each  occur-
                      rence  of replstr.  A maximum of 5 arguments in initial-
                      arguments may each contain  one  or  more  instances  of
                      replstr.   SPACE  and TAB characters at the beginning of
                      each line are thrown away.   Constructed  arguments  may
                      not  grow  larger  than 255 characters, and option -x is
                      also forced.  {} is assumed for replstr  if  not  speci-
                      fied.

       -lnumber       command  is  executed  for each nonempty number lines of
                      arguments from the standard input.  The last  invocation
                      of  command  will  be  with  fewer lines of arguments if
                      fewer than number remain.  A line is considered  to  end
                      with  the first NEWLINE unless the last character of the
                      line is a SPACE or a TAB; a trailing SPACE or  TAB  sig-
                      nals  continuation  through the next non-empty line.  If
                      number is omitted, 1  is  assumed.   The  -x  option  is
                      forced.

       -nnumber       Execute  command  using as many standard input arguments
                      as possible, up  to  number  arguments  maximum.   Fewer
                      arguments  will  be  used if their total size is greater
                      than size characters, and for  the  last  invocation  if
                      there  are  fewer  than  number arguments remaining.  If
                      option -x is also coded, each number arguments must  fit
                      in the size limitation, else xargs terminates execution.

       -ssize         The  maximum  total size of each argument list is set to
                      size characters; size must be a  positive  integer  less
                      than  or  equal to 470. If -s is not coded, 470 is taken
                      as the default.  Note:  the  character  count  for  size
                      includes  one  extra character for each argument and the
                      count of characters in the command name.

EXAMPLES
       The following will move all files from directory $1  to  directory  $2,
       and echo each move command just before doing it:

              ls $1 | xargs -i -t mv $1/{} $2/{}

       The  following  will  combine  the output of the parenthesized commands
       onto one line, which is then echoed to the end of file log:

              (logname; date; echo $0 $*) | xargs >>>>log

       The user is asked which files  in  the  current  directory  are  to  be
       archived  and  archives  them  into arch(1) one at a time, or many at a
       time.

              ls | xargs -p -l ar r arch
              ls | xargs -p -l | xargs ar r arch

       The following will execute diff(1) with successive pairs  of  arguments
       originally typed as shell arguments:

              echo $* | xargs -n2 diff

SEE ALSO
       arch(1), diff(1), sh(1)



                               17 September 1989                     XARGS(1V)