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bfs(1)                           User Commands                          bfs(1)



NAME
       bfs - big file scanner

SYNOPSIS
       /usr/bin/bfs [-] filename

DESCRIPTION
       The  bfs command is (almost) like ed(1) except that it is read-only and
       processes much larger files. Files can be up to  1024K  bytes  and  32K
       lines, with up to 512 characters, including new-line, per line (255 for
       16-bit machines). bfs is usually more efficient than ed(1) for scanning
       a file, since the file is not copied to a buffer. It is most useful for
       identifying sections of a large file where csplit(1)  can  be  used  to
       divide it into more manageable pieces for editing.

       Normally, the size of the file being scanned is printed, as is the size
       of any file written with the w (write) command.  The  optional  -  sup-
       presses printing of sizes. Input is prompted with * if P and a carriage
       return are typed, as in ed(1). Prompting can be  turned  off  again  by
       inputting  another  P and carriage return. Note that messages are given
       in response to errors if prompting is turned on.

       All address expressions described under ed(1) are supported.  In  addi-
       tion,  regular expressions may be surrounded with two symbols besides /
       and ?:

       >>        indicates downward search without wrap-around, and



       <&lt;        indicates upward search without wrap-around.



       There is a slight difference in mark names; that is, only the letters a
       through z may be used, and all 26 marks are remembered.

   bfs Commands
       The  e,  g, v, k, p, q, w, =, !, and null commands operate as described
       under ed(1). Commands such  as  ---,  +++-,  +++=,  -12,  and  +4p  are
       accepted.  Note  that  1,10p  and  1,10  will both print  the first ten
       lines. The f command only prints the name of the  file  being  scanned;
       there  is  no   remembered  file name. The  w command is independent of
       output diversion, truncation, or crunching (see the xo, xt, and xc com-
       mands, below). The following additional commands are available:

       xf file

           Further  commands  are  taken from the named file.  When an end-of-
           file is reached, an  interrupt  signal  is  received  or  an  error
           occurs,  reading  resumes  with  the file containing the xf. The xf
           commands may be nested to a depth of 10.



       xn

           List the marks currently in use (marks are set by the k command).



       xo [file]

           Further output from the p and null  commands  is  diverted  to  the
           named  file, which, if necessary, is created mode 666 (readable and
           writable by everyone), unless your  umask  setting  (see  umask(1))
           dictates  otherwise.  If file is missing, output is diverted to the
           standard output. Note that each diversion causes truncation or cre-
           ation of the file.



       : label

           This  positions  a label in a command file. The label is terminated
           by new-line, and blanks between the : (colon) and the start of  the
           label are ignored. This command may also be used to insert comments
           into a command file, since labels need not be referenced.



       ( . , . )xb/regular expression/label

           A jump (either upward or downward) is made to label if the  command
           succeeds. It fails under any of the following conditions:

               1.  Either address is not between 1 and $.


               2.  The second address is less than the first.


               3.  The  regular expression does not match at least one line in
                   the specified range, including the first and last lines.



           On success, . (dot) is set to the line matched and a jump  is  made
           to label. This command is the only one that does not issue an error
           message on bad addresses,  so  it  may  be  used  to  test  whether
           addresses are bad before other commands are executed. Note that the
           command, xb/^/ label, is an unconditional jump.

           The xb command is allowed only if it is read from  someplace  other
           than a terminal. If it is read from a pipe, only a downward jump is
           possible.



       xt number

           Output from the p and null commands is truncated to, at most,  num-
           ber characters. The initial number is 255.



       xv[digit][spaces][value]

           The variable name is the specified digit following the xv. The com-
           mands xv5100 or xv5 100 both assign the value  100 to the  variable
           5.  The  command xv61,100p assigns the value 1,100p to the variable
           6. To reference a variable, put a % in front of the variable  name.
           For example, using the above assignments for variables 5 and 6:



           1,%5p
           1,%5
           %6



           will all print the first 100 lines.


           g/%5/p


           would  globally  search  for the characters 100 and print each line
           containing a match. To escape the special meaning of %,  a  \  must
           precede it.


           g/".*\%[cds]/p


           could be used to match and list %c, %d, or %s formats (for example,
           "printf"-like  statements)  of  characters,  decimal  integers,  or
           strings.  Another  feature of the xv command is that the first line
           of output from a UNIX system command can be stored into a variable.
           The  only requirement is that the first character of value be an !.
           For example:



           .w junk
           xv5!cat junk
           !rm junk
           !echo "%5"
           xv6!expr %6 + 1



           would put the current line into variable 35, print it,  and  incre-
           ment  the variable 36 by one. To escape the special meaning of ! as
           the first character of value, precede it with a \.


           xv7\!date


           stores the value !date into variable 7.



       xbz label
       xbn label

           These two commands will test the last saved return  code  from  the
           execution  of  a  UNIX  system command (!command) or nonzero value,
           respectively, to the specified label. The two examples  below  both
           search for the next five lines containing the string size:


           Example 1:
                           xv55
                           : l
                           /size/
                           xv5!expr %5 - 1
                           !if 0%5 != 0 exit 2
                           xbn l






           Example 2:
                           xv45
                           : l
                           /size/
                           xv4!expr %4 - 1
                           !if 0%4 = 0 exit 2
                           xbz l




       xc [switch]

           If switch is 1, output from the p and null commands is crunched; if
           switch is 0, it is not. Without an argument,  xc  reverses  switch.
           Initially,  switch  is  set  for  no crunching. Crunched output has
           strings of tabs and blanks reduced to one  blank  and  blank  lines
           suppressed.



OPERANDS
       The following operand is supported:

       filename        Any  file  up  to 1024K bytes and 32K lines, with up to
                       512 characters, including new-line, per line  (255  for
                       16-bit machines). filename can be a section of a larger
                       file which has been divided into more  manageable  sec-
                       tions for editing by the use of csplit(1).



EXIT STATUS
       The following exit values are returned:

       0        Successful completion without any file or command errors.



       >&gt;0       An error occurred.



ATTRIBUTES
       See attributes(5) for descriptions of the following attributes:


       tab()     allbox;     cw(2.750000i)|    cw(2.750000i)    lw(2.750000i)|
       lw(2.750000i).  ATTRIBUTE TYPEATTRIBUTE VALUE AvailabilitySUNWesu


SEE ALSO
       csplit(1), ed(1), umask(1), attributes(5)

DIAGNOSTICS
       Message is ? for errors in commands, if prompting is turned off.  Self-
       explanatory error messages are displayed when prompting is on.



SunOS 5.10                        20 May 1996                           bfs(1)