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

     xargs - construct argument list(s) and execute utility

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

     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 characters, 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 specified size
             or there are fewer than number arguments remaining for the last
             invocation of utility.  The current default value for number is

     -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 (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)
             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.

     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.

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

     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.

     The xargs command appeared in PWB UNIX.

     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 11.0-PRERELEASE           May 7, 2001          FreeBSD 11.0-PRERELEASE


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