XARGS(1) DOMAIN/IX SYS5 XARGS(1)
NAME
xargs - construct argument list(s) and execute a command
USAGE
xargs [ options ] [ command [ initial arguments ] ]
DESCRIPTION
Xargs combines the fixed initial arguments with arguments
read from standard input to execute the specified command
one or more times. The options that you specify determine
the number of arguments read for each command invocation and
the manner in which they are combined.
Xargs uses your $PATH to search for command, which may be a
Shell file. If you omit command, it uses the /bin/echo com-
mand.
Arguments read in from standard input are defined to be con-
tiguous strings of characters delimited by one or more
blanks, tabs, or newlines; empty lines are always discarded.
Blanks and tabs may be embedded as part of an argument if
escaped or quoted. Characters enclosed in quotes (single or
double) are taken literally, and the delimiting quotes are
removed. Outside quoted strings, a backslash (\) escapes
the next character.
Each argument list begins with the initial arguments, fol-
lowed by some number of arguments read from standard input
(with the exception of those using the -i option). The -i,
-l, and -n options determine how arguments are selected for
each command invocation. When none of these options are
coded, the initial arguments are followed by arguments read
continuously from standard input until an internal buffer is
full. Then, command is executed with the accumulated argu-
ments. Xargs repeats this process until there are no more
arguments. When options conflict (e.g., -l vs. -n), the
last option has precedence.
OPTIONS
-lnumber Execute the command for each non-empty number
lines of arguments from standard input. The
last invocation of command will be with fewer
lines of arguments if fewer than number
remain. A line is considered to end with the
first newline unless the last character of
the line is a blank or a tab. A trailing
blank/tab signals continuation through the
next non-empty line. If number is omitted,
one is assumed. The -x option is forced.
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XARGS(1) DOMAIN/IX SYS5 XARGS(1)
-ireplstr Insert mode: execute command for each line
from standard input, taking the entire line
as a single argument, inserting it in initial
arguments for each occurrence of replstr. A
maximum of five arguments in initial argu-
ments may each contain one or more instances
of replstr. Discard blanks and tabs at the
beginning of each line. Constructed argu-
ments may not grow larger than 255 charac-
ters, and option -x is also forced. Braces
({}) are assumed for replstr if not speci-
fied.
-nnumber Execute command using as many standard input
arguments as possible, up to number arguments
maximum. Fewer arguments will be used if
their total size is greater than size charac-
ters, and for the last invocation if there
are fewer than number arguments remaining.
If option -x is also coded, each number argu-
ments must fit in the size limitation. Oth-
erwise, xargs terminates execution.
-t Trace mode: echo command and each constructed
argument list to file descriptor 2 just prior
to their execution.
-p Prompt mode: ask whether or not to execute
command each invocation. Turn on trace mode
(-t) to print the command instance to be exe-
cuted, followed by a ?... prompt. Replying
with a y (optionally followed by anything)
executes the command. Anything else, includ-
ing a simple carriage return, skips that par-
ticular invocation of command.
-x Terminate xargs if any argument list is
greater than size characters. The -x option
is forced by the -i and -l options. When the
-i, -l, or -n options are coded, the total
length of all arguments must be within the
size limit.
-ssize Set the maximum total size of each argument
list to size characters. Size must be a
positive integer less than or equal to 470.
If the -s option is not coded, 470 becomes
the default. Note that the character count
for size includes one extra character for
each argument and the count of characters in
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XARGS(1) DOMAIN/IX SYS5 XARGS(1)
the command name.
-eeofstr Use eofstr as the logical end-of-file string.
An underscore (_) is assumed for the logical
EOF string if the -e option is not coded.
The value of -e with no eofstr coded turns
off the logical EOF string capability (an
underscore is taken literally). Xargs reads
standard input until it encounters either an
end-of-file or the logical EOF string.
EXAMPLES
To move all files from directory $1 to directory $2, and to
echo each move command just before executing, use the fol-
lowing:
ls $1 | xargs -i -t mv $1/{} $2/{}
To combine the output of the parenthesized commands onto one
line, which is then echoed to the end of file log, use this:
(logname; date; echo $0 $*) | xargs >>log
To execute diff(1) with successive pairs of arguments origi-
nally typed as Shell arguments:
echo $* | xargs -n2 diff
CAUTIONS
Xargs terminates if it receives a return code of -1 from, or
if it cannot execute, command. When command is a Shell pro-
gram, it should explicitly exit with an appropriate value to
avoid accidentally returning with -1. Consult sh(1) for
more information about how the Shell works.
DIAGNOSTICS
Self-explanatory.
RELATED INFORMATION
sh(1).
Printed 12/4/86 XARGS-3