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XARGS(1)			   BSD 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 arguments from the
     standard input and executes the specified utility with them as arguments.

     The utility and any arguments specified on the command line are given to the utility upon
     each invocation, followed by some number of the arguments read from standard input.  The
     utility is repeatedly executed until standard 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 charac-
     ters, excluding newlines, up to the matching single quote.  Double quotes escape all non-
     double quote characters, 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 occurences 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 concatenating 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 distinct 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
	     the 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 speci-
	     fied 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 replacement in.

     -s size
	     Set the maximum number of bytes for the command line length provided to utility.
	     The sum of the length of the utility name, the arguments passed to utility (includ-
	     ing 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) command line length.

     If no utility is specified, 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 the utility is terminated
     by a signal or an invocation of the 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'') compliant.  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.

BSD					   May 7, 2001					      BSD
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