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XARGS(1)		FreeBSD	General	Commands Manual		      XARGS(1)

NAME
     xargs -- construct	argument list(s) and execute utility

SYNOPSIS
     xargs [-0pt] [-E eofstr] [-I replstr [-R replacements]] [-J replstr]
	   [-L number] [-n number [-x]]	[-s size] [utility [argument ...]]

DESCRIPTION
     The xargs utility reads space, tab, newline and end-of-file delimited
     strings from the standard input and executes utility with the strings as
     arguments.

     Any arguments specified on	the command line are given to utility upon
     each invocation, followed by some number of the arguments read from the
     standard input of xargs.  The utility is repeatedly executed until	stan-
     dard input	is exhausted.

     Spaces, tabs and newlines may be embedded in arguments using single
     (`` ' '') or double (``"'') quotes	or backslashes (``\'').	 Single	quotes
     escape all	non-single quote characters, excluding newlines, up to the
     matching single quote.  Double quotes escape all non-double quote charac-
     ters, excluding newlines, up to the matching double quote.	 Any single
     character,	including newlines, may	be escaped by a	backslash.

     The options are as	follows:

     -0	     Change xargs to expect NUL	(``\0'') characters as separators,
	     instead of	spaces and newlines.  This is expected to be used in
	     concert with the -print0 function in find(1).

     -E	eofstr
	     Use eofstr	as a logical EOF marker.

     -I	replstr
	     Execute utility for each input line, replacing one	or more	occur-
	     rences of replstr in up to	replacements (or 5 if no -R flag is
	     specified)	arguments to utility with the entire line of input.
	     The resulting arguments, after replacement	is done, will not be
	     allowed to	grow beyond 255	bytes; this is implemented by concate-
	     nating as much of the argument containing replstr as possible, to
	     the constructed arguments to utility, up to 255 bytes.  The 255
	     byte limit	does not apply to arguments to utility which do	not
	     contain replstr, and furthermore, no replacement will be done on
	     utility itself.  Implies -x.

     -J	replstr
	     If	this option is specified, xargs	will use the data read from
	     standard input to replace the first occurrence of replstr instead
	     of	appending that data after all other arguments.	This option
	     will not effect how many arguments	will be	read from input	(-n),
	     or	the size of the	command(s) xargs will generate (-s).  The
	     option just moves where those arguments will be placed in the
	     command(s)	that are executed.  The	replstr	must show up as	a dis-
	     tinct argument to xargs.  It will not be recognized if, for
	     instance, it is in	the middle of a	quoted string.	Furthermore,
	     only the first occurrence of the replstr will be replaced.	 For
	     example, the following command will copy the list of files	and
	     directories which start with an uppercase letter in the current
	     directory to destdir:

		   /bin/ls -1d [A-Z]* |	xargs -J % cp -rp % destdir

     -L	number
	     Call utility for every number lines read.	If EOF is reached and
	     fewer lines have been read	than number then utility will be
	     called with the available lines.

     -n	number
	     Set the maximum number of arguments taken from standard input for
	     each invocation of	utility.  An invocation	of utility will	use
	     less than number standard input arguments if the number of	bytes
	     accumulated (see the -s option) exceeds the specified size	or
	     there are fewer than number arguments remaining for the last
	     invocation	of utility.  The current default value for number is
	     5000.

     -p	     Echo each command to be executed and ask the user whether it
	     should be executed.  An affirmative response, `y' in the POSIX
	     locale, causes the	command	to be executed,	any other response
	     causes it to be skipped.  No commands are executed	if the process
	     is	not attached to	a terminal.

     -R	replacements
	     Specify the maximum number	of arguments that -I will do replace-
	     ment in.

     -s	size
	     Set the maximum number of bytes for the command line length pro-
	     vided to utility.	The sum	of the length of the utility name, the
	     arguments passed to utility (including NULL terminators) and the
	     current environment will be less than or equal to this number.
	     The current default value for size	is ARG_MAX - 4096.

     -t	     Echo the command to be executed to	standard error immediately
	     before it is executed.

     -x	     Force xargs to terminate immediately if a command line containing
	     number arguments will not fit in the specified (or	default) com-
	     mand line length.

     If	utility	is omitted, echo(1) is used.

     Undefined behavior	may occur if utility reads from	the standard input.

     The xargs utility exits immediately (without processing any further
     input) if a command line cannot be	assembled, utility cannot be invoked,
     an	invocation of utility is terminated by a signal, or an invocation of
     utility exits with	a value	of 255.

DIAGNOSTICS
     The xargs utility exits with a value of 0 if no error occurs.  If utility
     cannot be found, xargs exits with a value of 127, otherwise if utility
     cannot be executed, xargs exits with a value of 126.  If any other	error
     occurs, xargs exits with a	value of 1.

SEE ALSO
     echo(1), find(1), execvp(3)

STANDARDS
     The xargs utility is expected to be IEEE Std 1003.2 (``POSIX.2'') compli-
     ant.  The -J and -R options are non-standard FreeBSD extensions which may
     not be available on other operating systems.

HISTORY
     The xargs command appeared	in PWB UNIX.

BUGS
     If	utility	attempts to invoke another command such	that the number	of
     arguments or the size of the environment is increased, it risks execvp(3)
     failing with E2BIG.

FreeBSD	9.2			  May 7, 2001			   FreeBSD 9.2

NAME | SYNOPSIS | DESCRIPTION | DIAGNOSTICS | SEE ALSO | STANDARDS | HISTORY | BUGS

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