The
utility reads space, tab, newline and end-of-file delimited strings
from the standard input and executes
utility
with the strings as
arguments.
Any arguments specified on the command line are given to
utility
upon each invocation, followed by some number of the arguments read
from the standard input of
.
This is repeated 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
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 occurrences 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
replsize
(or 255 if no
-S
flag is specified)
bytes; this is implemented by concatenating as much of the argument
containing
replstr
as possible, to the constructed arguments to
utility
up to
replsize
bytes.
The size 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,
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 affect how many arguments will be read from input
(-n
)
or the size of the command(s)
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
.
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
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 5000.
-o
Reopen stdin as
/dev/tty
in the child process before executing the command.
This is useful if you want
to run an interactive application.
-P maxprocs
Parallel mode: run at most
maxprocs
invocations of
utility
at once.
-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
Compatibility with GNU
.
The GNU version of
runs the
utility
argument at least once, even if
input is empty, and it supports a
-r
option to inhibit this behavior.
The
Fx version of
does not run the
utility
argument on empty input, but it supports the
-r
option for command-line compatibility with GNU
,
but the
-r
option does nothing in the
Fx version of
.
-R replacements
Specify the maximum number of arguments that
-I
will do replacement in.
If
replacements
is negative, the number of arguments in which to replace is unbounded.
-S replsize
Specify the amount of space (in bytes) that
-I
can use for replacements.
The default for
replsize
is 255.
-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
to terminate immediately if a command line containing
number
arguments will not fit in the specified (or default) command line length.
Undefined behavior may occur if
utility
reads from the standard input.
The
utility exits immediately (without processing any further input) if a
command line cannot be assembled,
utility
cannot be invoked, an invocation of
utility
is terminated by a signal,
or an invocation of
utility
exits with a value of 255.
EXIT STATUS
The
utility exits with a value of 0 if no error occurs.
If
utility
cannot be found,
exits with a value of 127, otherwise if
utility
cannot be executed,
exits with a value of 126.
If any other error occurs,
exits with a value of 1.
The
utility is expected to be
St -p1003.2
compliant.
The
-J , o , P, R
and
-S
options are non-standard
Fx extensions which may not be available on other operating systems.
HISTORY
The
utility appeared in PWB UNIX.
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
Er E2BIG .
The
utility does not take multibyte characters into account when performing
string comparisons for the
-I
and
-J
options, which may lead to incorrect results in some locales.
