xargs(1) - NetBSD Manual Pages

XARGS(1)                NetBSD General Commands Manual                XARGS(1)


NAME

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


SYNOPSIS

     xargs [-0] [-p] [-t] [[-x] -n number] [-s size] [utility [arguments ...]]


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 argu-
     ments 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 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          Use NUL (``\0'') instead of whitespace as the argument sepa-
                 rator, and do not perform any of the quoting described above
                 (all non-\0 characters are treated equivalently).  This can
                 be used in conjunction with the -print0 option of find(1).

     -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
                 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          Prompt mode: immediately before each command execution the
                 user is prompted whether to execute the command instance.  If
                 an affirmative response is read from /dev/tty the command
                 will be executed; otherwise this particular invocation will
                 be skipped.  This option implies the -t option.

     -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 and the arguments passed to utility (including NULL ter-
                 minators) 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 con-
                 taining 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.


EXIT STATUS

     xargs exits with one of the following values:
     0       All invocations of utility returned a zero exit status.
     123     One or more invocations of utility returned a nonzero exit sta-
             tus.
     124     The utility exited with a 255 exit status.
     125     The utility was killed or stopped by a signal.
     126     The utility was found but could not be invoked.
     127     The utility could not be found.
     1       Some other error occurred.


FILES

     /dev/tty  used to read responses in prompt mode


SEE ALSO

     echo(1), find(1)


STANDARDS

     The xargs utility is expected to be IEEE Std 1003.2 (``POSIX.2'') compli-
     ant.


HISTORY

     The xargs command appeared in PWB Unix 1.0.  It made its first BSD
     appearance in the 4.3 Reno release.

     The meaning of 123, 124, and 125 exit values and the -0 option were taken
     from GNU xargs.

NetBSD 4.0                      August 11, 2006                     NetBSD 4.0