Manual Pages for UNIX Darwin command on man xargs

XARGS(1) BSD General Commands Manual XARGS(1)

NAME

xxaarrggss - construct argument list(s) and execute utility

SYNOPSIS

xxaarrggss [-00pptt] [-EE eofstr] [-II replstr [-RR replacements]] [-JJ replstr]

[-LL number] [-nn number [-xx]] [-ss size] [utility [argument ...]]

DESCRIPTION

The xxaarrggss 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:

-00 Change xxaarrggss to expect NUL (``\0'') characters as separators,

instead of spaces and newlines. This is expected to be used in

concert with the -pprriinntt00 function in find(1).

-EE eofstr

Use eofstr as a logical EOF marker.

-II replstr

Execute utility for each input line, replacing one or more

occurences of replstr in up to replacements (or 5 if no -RR 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 concate-

nating 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 -xx.

-JJ replstr

If this option is specified, xxaarrggss 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 (-nn),

or the size of the command(s) xxaarrggss will generate (-ss). The

option just moves where those arguments will be placed in the

command(s) that are executed. The replstr must show up as a dis-

tinct argument to xxaarrggss. 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

-LL 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.

-nn 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 -ss 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.

-pp 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.

-RR replacements

Specify the maximum number of arguments that -II will do replace-

ment in.

-ss size

Set the maximum number of bytes for the command line length pro-

vided 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 ARGMAX - 4096.

-tt Echo the command to be executed to standard error immediately

before it is executed.

-xx Force xxaarrggss to terminate immediately if a command line containing

number arguments will not fit in the specified (or default) com-

mand line length. If no utility is specified, echo(1) is used. Undefined behavior may occur if utility reads from the standard input. The xxaarrggss 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 xxaarrggss utility exits with a value of 0 if no error occurs. If utility cannot be found, xxaarrggss exits with a value of 127, otherwise if utility cannot be executed, xxaarrggss exits with a value of 126. If any other error occurs, xxaarrggss exits with a value of 1.

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