xargs: Construct argument list(s) and invoke utility Usage: xargs [-CtTxh-] [-o<opt>] [-e<escape>] [-X <errlimit>] [-n <number>] [-s <size>] [-r<string>] [<utility> [<arguments>]] xargs will construct a command line consisting of the specified utility name and arguments followed by as many arguments read from stdin as will fit, given the constraints of the operating system or as specified by the -n and -s options. xargs then invokes that constructed command and waits for it to complete. This sequence is repeated until end-of-file is detected on stdin or until a constructed command exits with return code greater than 1 or some other specified value. (The value of 1 was chosen so that commands like grep and fgrep that exit with 1 if no matches are found in a given set will continue.) Arguments in the input can be separated by unquoted, unescaped white space (spaces, tabs, carriage returns or newlines). Quotes can be used around any text containing spaces or tabs. An escape character can be used at the end of a line to embed a carriage return-newline sequence. The generated command line length is the sum of the size in bytes of the utility name and each argument, including a space between each argument, a terminating null at the end, and any quotes or escape characters as may be dictated by the operating system conventions for embedding any special characters. Options: -C Start up a copy of C shell to run each command. -t Trace mode. Each generated command line is written to stderr just prior to invocation. -T Change the title bar for each iteration. -x Terminate if a command line containing the number of arguments specified with the -n option will not fit on the implied or specified command line. -o<opt> Additional startup options for the C shell. For example, to get a fast startup, use -oF. -e<escape> Escape character. By default, xargs will use the character specified by the ESCAPESYM environment variable (if defined) or, if not defined, the circumflex ("^"). -X <errlimit> Error limit. If a child command exits with a return code greater than the specified <errlimit>, xargs will exit with that return code from the child. By default, xargs will exit with the first return code > 1. -n <number> Invoke <utility> with up to <number> arguments. Fewer arguments are used if (a) the command line length exceeds the size limit or (b) the last iteration contains fewer, but not zero operands. By default, there is no <number> limit. -s <size> Invoke <utility> using as many arguments as possible to produce a command line less than <size> bytes in length. Fewer arguments are used if (a) the total number of arguments exceeds the <number> limit or (b) end-of-file is encountered on stdin before <size> bytes are accumulated. By default, there is a <size> limit of 32280 characters for a Win32, POSIX or OS/2 application; for a DOS or Win3.x application, the limit is 110 characters. If the C shell is being invoked to run a command that's suspected to be a C shell alias, xargs reduces the 32280 limit by 1024 characters to allow for possible expansion. -r<string> Replace the first argument word which consists of only the specified string with argument words read from stdin. Default string is "%%". <utility> The name of the utility to be invoked. This can be a fully-qualified or relative pathname or a name resolved by searching the directories listed in the PATH environment variable. As needed, xargs will look for files with a .csh, .exe, .com or .cmd or .bat extension, auto- matically invoking the C shell for .csh files and the standard command processor for .cmd or .bat files. If a suitable executable file cannot be found, xargs will assume it may be a C shell alias or built-in command. If no utility is specified, a built-in echo utility is used. <arguments> Initial options or operands to <utility>. -h Help. (This screen.) -- End of options. |