xargs(1)							   User Commands							  xargs(1)

NAME

       xargs - construct argument lists and invoke utility

SYNOPSIS

       xargs [-t] [-p] [-e[eofstr]] [-E eofstr]
	    [-I replstr] [-i[replstr]] [-L number] [-l[number]]
	    [-n number [-x]] [-s size] [utility [argument...]]

DESCRIPTION

       The xargs utility constructs a command line consisting of the utility and argument operands specified followed by as many arguments read in
       sequence from standard input as fit in length and number constraints specified by the options. The xargs  utility  then	invokes  the  con-
       structed  command line and waits for its completion. This sequence is repeated until an end-of-file condition is detected on standard input
       or an invocation of a constructed command line returns an exit status of 255.

       Arguments in the standard input must be separated by unquoted blank characters, or unescaped blank  characters  or  newline  characters.  A
       string  of  zero or more non-double-quote (") and non-newline characters can be quoted by enclosing them in double-quotes. A string of zero
       or more non-apostrophe (') and non-newline characters can be quoted by enclosing them in apostrophes. Any unquoted character can be escaped
       by preceding it with a backslash (). The utility are executed one or more times until the end-of-file is reached. The results are unspeci-
       fied if the utility named by utility attempts to read from its standard input.

       The generated command line length is the sum of the size in bytes of the utility name and each argument treated	as  strings,  including  a
       null  byte  terminator  for  each  of  these  strings.  The xargs utility limits the command line length such that when the command line is
       invoked, the combined argument and environment lists can not exceed {ARG_MAX}-2048 bytes. Within this constraint, if neither the -n nor the
       -s option is specified, the default command line length is at least {LINE_MAX}.

OPTIONS

       The following options are supported:

       -e[eofstr]     Uses  eofstr as the logical end-of-file string. Underscore (_) is assumed for the logical EOF string if neither -e nor -E is
		      used. When the eofstr option-argument is omitted, the logical EOF string capability is disabled and  underscores	are  taken
		      literally. The xargs utility reads standard input until either end-of-file or the logical EOF string is encountered.

       -E eofstr      Specifies  a  logical  end-of-file string to replace the default underscore. xargs reads standard input until either end-of-
		      file or the logical EOF string is encountered. When eofstr is a null string, the logical end-of-file  string  capability	is
		      disabled and underscore characters are taken literally.

       -I replstr     Insert  mode.  utility is executed for each line from standard input, taking the entire line as a single argument, inserting
		      it in argument s for each occurrence of replstr. A maximum of five arguments in arguments  can  each  contain  one  or  more
		      instances  of  replstr.  Any  blank  characters at the beginning of each line are ignored. Constructed arguments cannot grow
		      larger than 255 bytes. Option -x is forced on. The -I and -i options are mutually exclusive; the last  one  specified  takes
		      effect.

       -i[replstr]    This option is equivalent to -I replstr. The string {} is assumed for replstr if the option-argument is omitted.

       -L number      The  utility is executed for each non-empty number lines of arguments from standard input. The last invocation of utility is
		      with fewer lines of arguments if fewer than number remain. A line is considered to end  with  the  first	newline  character
		      unless the last character of the line is a blank character; a trailing blank character signals continuation to the next non-
		      empty line, inclusive. The -L, -l, and -n options are mutually exclusive; the last one specified takes effect.

       -l[number]     (The letter ell.) This option is equivalent to -L number. If number is omitted, 1 is assumed. Option -x is forced on.

       -n number      Invokes utility using as many standard input arguments as possible, up to number (a positive decimal integer) arguments max-
		      imum. Fewer arguments are used if:

			  o	 The  command line length accumulated exceeds the size specified by the -s option (or {LINE_MAX} if there is no -s
				 option), or

			  o	 The last iteration has fewer than number, but not zero, operands remaining.

       -p	      Prompt mode. The user is asked whether to execute utility at each invocation. Trace mode (-t) is turned on to write the com-
		      mand  instance  to  be  executed,  followed  by  a prompt to standard error. An affirmative response (specific to the user's
		      locale) read from /dev/tty executes the command; otherwise, that particular invocation of utility is skipped.

       -s size	      Invokes utility using as many standard input arguments as possible yielding a command line length less than size (a positive
		      decimal integer) bytes. Fewer arguments are used if:

			  o	 The total number of arguments exceeds that specified by the -n option, or

			  o	 The total number of lines exceeds that specified by the -L option, or

			  o	 End of file is encountered on standard input before size bytes are accumulated.
		      Values  of  size	up  to at least {LINE_MAX} bytes are supported, provided that the constraints specified in DESCRIPTION are
		      met. It is not considered an error if a value larger than that supported by the implementation or exceeding the  constraints
		      specified in DESCRIPTION is specified. xargs uses the largest value it supports within the constraints.

       -t    Enables trace mode. Each generated command line is written to standard error just prior to invocation.

       -x    Terminates if a command line containing number arguments (see the -n option above) or number lines (see the -L option above) does not
	     fit in the implied or specified size (see the -s option above).

OPERANDS

       The following operands are supported:

       utility	   The name of the utility to be invoked, found by search path using the PATH environment variable. (ee environ(5).) If utility is
		   omitted,  the  default  is  the  echo(1)  utility.  If  the	utility  operand  names  any  of the special built-in utilities in
		   shell_builtins(1), the results are undefined.

       argument    An initial option or operand for the invocation of utility.

USAGE

       The 255 exit status allows a utility being used by xargs to tell xargs to terminate if it knows no further invocations  using  the  current
       data stream succeeds. Thus, utility should explicitly exit with an appropriate value to avoid accidentally returning with 255.

       Notice  that  input  is	parsed	as lines. Blank characters separate arguments. If xargs is used to bundle output of commands like find dir
       -print or ls into commands to be executed, unexpected results are likely if any filenames contain any blank characters or  newline  charac-
       ters.  This  can  be  fixed  by using find to call a script that converts each file found into a quoted string that is then piped to xargs.
       Notice that the quoting rules used by xargs are not the same as in the shell. They were not made consistent here because existing  applica-
       tions  depend  on  the  current	rules and the shell syntax is not fully compatible with it. An easy rule that can be used to transform any
       string into a quoted form that xargs interprets correctly is to precede each character in the string with a backslash ().

       On implementations with a large value for {ARG_MAX}, xargs can produce command lines longer than {LINE_MAX}. For invocation  of	utilities,
       this  is  not a problem. If xargs is being used to create a text file, users should explicitly set the maximum command line length with the
       -s option.

       The xargs utility returns exit status 127 if an error occurs so that applications can distinguish "failure to find a utility" from "invoked
       utility	exited	with an error indication." The value 127 was chosen because it is not commonly used for other meanings; most utilities use
       small values for "normal error conditions" and the values above 128 can be confused with termination due to receipt of a signal. The  value
       126 was chosen in a similar manner to indicate that the utility could be found, but not invoked.

EXAMPLES

       Example 1 Using the xargs command

       The following example moves all files from directory $1 to directory $2, and echo each move command just before doing it:

	 example% ls $1 | xargs -I {} -t mv $1/{} $2/{}

       The following command combines the output of the parenthesised commands onto one line, which is then written to the end of file log:

	 example% (logname; date; printf "%s
" "$0 $*") | xargs >>log

       The  following  command	invokes  diff with successive pairs of arguments originally typed as command line arguments (assuming there are no
       embedded blank characters in the elements of the original argument list):

	 example% printf "%s
" "$*" | xargs -n 2 -x diff

       The user is asked which files in the current directory are to be archived. The files are archived into arch ; a, one at a time, or b,  many
       at a time:

	 example% ls | xargs -p -L 1 ar -r arch
	 ls | xargs -p -L 1 | xargs ar -r arch

       The following executes with successive pairs of arguments originally typed as command line arguments:

	 example% echo $* | xargs -n 2 diff

ENVIRONMENT VARIABLES

       See  environ(5)	for  descriptions  of  the  following  environment variables that affect the execution of xargs: LANG, LC_ALL, LC_COLLATE,
       LC_CTYPE, LC_MESSAGES, and NLSPATH.

       PATH    Determine the location of utility.

       Affirmative responses are processed using the extended regular expression defined for the yesexpr keyword in the  LC_MESSAGES  category	of
       the user's locale. The locale specified in the LC_COLLATE category defines the behavior of ranges, equivalence classes, and multi-character
       collating elements used in the expression defined for yesexpr. The locale specified in LC_CTYPE determines the locale for interpretation of
       sequences  of  bytes  of  text  data  a	characters,  the behavior of character classes used in the expression defined for the yesexpr. See
       locale(5).

EXIT STATUS

       The following exit values are returned:

       0	   All invocations of utility returned exit status 0.

       1-125	   A command line meeting the specified requirements could not be assembled, one or more of the invocations of utility returned  a
		   non-zero exit status, or some other error occurred.

       126	   The utility specified by utility was found but could not be invoked.

       127	   The utility specified by utility could not be found.

       If  a  command  line meeting the specified requirements cannot be assembled, the utility cannot be invoked, an invocation of the utility is
       terminated by a signal, or an invocation of the utility exits with exit status 255, the xargs utility writes a diagnostic message and  exit
       without processing any remaining input.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+
       |CSI			     |Enabled			   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       echo(1), shell_builtins(1), attributes(5), environ(5), standards(5)

SunOS 5.11							    17 Jul 2007 							  xargs(1)