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XARGS(1)							      XARGS(1)



NAME
       xargs - build and execute command lines from standard input

SYNOPSIS
       xargs  [-0prtx]	[-E  eof-str] [-e[eof-str]] [--eof[=eof-str]] [--null]
       [-d delimiter] [--delimiter delimiter]  [-I  replace-str]  [-i[replace-
       str]]	[--replace[=replace-str]]   [-l[max-lines]]   [-L   max-lines]
       [--max-lines[=max-lines]] [-n max-args] [--max-args=max-args] [-s  max-
       chars]  [--max-chars=max-chars]	[-P max-procs] [--max-procs=max-procs]
       [--interactive]	    [--verbose]      [--exit]	   [--no-run-if-empty]
       [--arg-file=file]  [--show-limits]  [--version] [--help] [command [ini
       tial-arguments]]

DESCRIPTION
       This manual page documents the GNU version of xargs.  xargs reads items
       from  the  standard  input, delimited by blanks (which can be protected
       with double or single quotes or a backslash) or newlines, and  executes
       the  command (default is /bin/echo) one or more times with any initial-
       arguments followed by items read from standard input.  Blank  lines  on
       the standard input are ignored.

       Because	Unix  filenames  can contain blanks and newlines, this default
       behaviour is often problematic; filenames containing blanks and/or new
       lines  are  incorrectly	processed by xargs.  In these situations it is
       better to use the -0 option, which  prevents  such  problems.	When
       using  this  option you will need to ensure that the program which pro
       duces the input for xargs also uses a null character  as  a  separator.
       If that program is GNU find for example, the -print0 option does this
       for you.

       If any invocation of the command exits with a status of 255, xargs will
       stop  immediately  without reading any further input.  An error message
       is issued on stderr when this happens.

   OPTIONS
       --arg-file=file, -a file
	      Read items from file instead of standard input.  If you use this
	      option,  stdin  remains unchanged when commands are run.	Other
	      wise, stdin is redirected from /dev/null.


       --null, -0
	      Input items are terminated by a null  character  instead	of  by
	      whitespace,  and the quotes and backslash are not special (every
	      character is taken literally).  Disables the end of file string,
	      which  is  treated  like	any other argument.  Useful when input
	      items might contain white space, quote  marks,  or  backslashes.
	      The  GNU	find  -print0  option produces input suitable for this
	      mode.

       --delimiter=delim, -d delim
	      Input items are terminated by the specified  character.	Quotes
	      and  backslash  are not special; every character in the input is
	      taken literally.	Disables  the  end-of-file  string,  which  is
	      treated  like  any  other  argument.   This can be used when the
	      input consists of simply newline-separated items, although it is
	      almost  always  better  to  design  your program to use --null
	      where this is possible.  The specified delimiter may be a single
	      character, a C-style character escape such as \n, or an octal or
	      hexadecimal escape code.	Octal and hexadecimal escape codes are
	      understood as for the printf command.   Multibyte characters are
	      not supported.


       -Eeof-str
	      Set the end of file string to  eof-str.	If  the  end  of  file
	      string  occurs  as  a  line  of  input, the rest of the input is
	      ignored.	If neither -E nor -e is used, no end of file string is
	      used.

       --eof[=eof-str], -e[eof-str]
	      This option is a synonym for the -E option.  Use -E instead,
	      because it is POSIX compliant while this option is not.  If eof-
	      str  is  omitted, there is no end of file string.  If neither -E
	      nor -e is used, no end of file string is used.

       --help Print a summary of the options to xargs and exit.

       -I replace-str
	      Replace occurrences of replace-str in the initial-arguments with
	      names  read  from  standard input.  Also, unquoted blanks do not
	      terminate input items; instead  the  separator  is  the  newline
	      character.  Implies -x and -L 1.

       --replace[=replace-str], -i[replace-str]
	      This  option  is	a  synonym for -Ireplace-str if replace-str is
	      specified, and for -I{} otherwise.  This option  is  deprecated;
	      use -I instead.

       -L max-lines
	      Use  at  most  max-lines	nonblank input lines per command line.
	      Trailing blanks cause an input line to be logically continued on
	      the next input line.  Implies -x.

       --max-lines[=max-lines], -l[max-lines]
	      Synonym for the -L option.  Unlike -L, the max-lines argument is
	      optional.  If max-args is not specified,	it  defaults  to  one.
	      The  -l  option is deprecated since the POSIX standard specifies
	      -L instead.

       --max-args=max-args, -n max-args
	      Use at most max-args arguments per  command  line.   Fewer  than
	      max-args	arguments will be used if the size (see the -s option)
	      is exceeded, unless the -x option is given, in which case  xargs
	      will exit.

       --interactive, -p
	      Prompt  the user about whether to run each command line and read
	      a line from the terminal.  Only run  the	command  line  if  the
	      response starts with y or Y.  Implies -t.

       --no-run-if-empty, -r
	      If the standard input does not contain any nonblanks, do not run
	      the command.  Normally, the command is run once even if there is
	      no input.  This option is a GNU extension.

       --max-chars=max-chars, -s max-chars
	      Use at most max-chars characters per command line, including the
	      command and initial-arguments and the terminating nulls  at  the
	      ends of the argument strings.  The default is 131072 characters,
	      not including the size of the environment variables  (which  are
	      provided	for separately so that it doesnt matter if your envi
	      ronment variables take up more than 131072 bytes).  The  operat
	      ing  system  places  limits  on the values that you can usefully
	      specify, and if you exceed these a warning  message  is  printed
	      and  the	value actually used is set to the appropriate upper or
	      lower limit.

       --verbose, -t
	      Print the command line on the standard error output before  exe
	      cuting it.

       --version
	      Print the version number of xargs and exit.

       --show-limits
	      Display  the limits on the command-line length which are imposed
	      by the operating system, xargs choice of buffer size and the -s
	      option.	Pipe  the  input  from	/dev/null (and perhaps specify
	      --no-run-if-empty) if you dont want xargs to do anything.

       --exit, -x
	      Exit if the size (see the -s option) is exceeded.

       --max-procs=max-procs, -P max-procs
	      Run up to max-procs processes at a time; the default is  1.   If
	      max-procs  is 0, xargs will run as many processes as possible at
	      a time.  Use the -n option with -P; otherwise chances  are  that
	      only one exec will be done.

EXAMPLES
       find /tmp -name core -type f -print | xargs /bin/rm -f

       Find  files  named core in or below the directory /tmp and delete them.
       Note that this will work incorrectly if there are  any  filenames  con
       taining newlines or spaces.

       find /tmp -name core -type f -print0 | xargs -0 /bin/rm -f

       Find  files  named core in or below the directory /tmp and delete them,
       processing filenames in such a way that file or	directory  names  con
       taining spaces or newlines are correctly handled.

       cut -d: -f1 < /etc/passwd | sort | xargs echo

       Generates a compact listing of all the users on the system.

EXIT STATUS
       xargs exits with the following status:
       0 if it succeeds
       123 if any invocation of the command exited with status 1-125
       124 if the command exited with status 255
       125 if the command is killed by a signal
       126 if the command cannot be run
       127 if the command is not found
       1 if some other error occurred.

       Exit  codes  greater  than 128 are used by the shell to indicate that a
       program died due to a fatal signal.

STANDARDS CONFORMANCE
       As of GNU xargs version 4.2.9, the default behaviour of xargs is not to
       have  a	logical end-of-file marker.  POSIX (IEEE Std 1003.1, 2004 Edi
       tion) allows this.

       The -l and -i options appear in the 1997 version of the POSIX standard,
       but  do	not appear in the 2004 version of the standard.  Therefore you
       should use -L and -I instead, respectively.


SEE ALSO
       find(1), locate(1), locatedb(5), updatedb(1), Finding Files (on-line in
       Info, or printed)

BUGS
       The  -L	option	is incompatible with the -I option, but perhaps should
       not be.

       It is not possible for xargs to be  used  securely,  since  there  will
       always  be a time gap between the production of the list of input files
       and their use in the commands that xargs issues.  If other  users  have
       access  to  the	system, they can manipulate the filesystem during this
       time window to force the action of the commands xargs runs to apply  to
       files  that  you didnt intend.  For a more detailed discussion of this
       and related problems, please refer to the  Security  Considerations
       chapter in the findutils Texinfo documentation.	The -execdir option of
       find can often be used as a more secure alternative.

       When you use the -I option, each line read from the input  is  buffered
       internally.    This means that there is an upper limit on the length of
       input line that xargs will accept when used with  the  -I  option.   To
       work  around this limitation, you can use the -s option to increase the
       amount of buffer space that xargs uses, and you can also use  an  extra
       invocation  of  xargs to ensure that very long lines do not occur.  For
       example:

       somecommand | xargs -s 50000 echo | xargs -I {} -s 100000 rm {}

       Here, the first invocation of xargs has	no  input  line  length  limit
       because	it  doesnt use the -i option.  The second invocation of xargs
       does have such a limit, but we have ensured that the it	never  encoun
       ters  a line which is longer than it can handle.   This is not an ideal
       solution.  Instead, the -i option  should  not  impose  a  line	length
       limit,  which  is why this discussion appears in the BUGS section.  The
       problem doesnt occur with the output of find(1) because it emits  just
       one filename per line.

       The  best  way  to  report  a  bug  is to use the form at http://savan
       nah.gnu.org/bugs/?group=findutils.  The reason for  this  is  that  you
       will then be able to track progress in fixing the problem.   Other com
       ments about xargs(1) and about the findutils package in general can  be
       sent  to  the bug-findutils mailing list.  To join the list, send email
       to bug-findutils-request@gnu.org.



								      XARGS(1)




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