A pipeline is a sequence of one or more commands separated by one of the control operators | or |&. The
format for a pipeline is:
[time [-p]] [ ! ] command [ [|⎪|&] command2 ... ]
The standard output of command is connected via a pipe to the standard input of command2. This
connection is performed before any redirections specified by the command (see REDIRECTION below). If |&
is used, the standard error of command is connected to command2's standard input through the pipe; it is
shorthand for 2>&1 |. This implicit redirection of the standard error is performed after any
redirections specified by the command.
The return status of a pipeline is the exit status of the last command, unless the pipefail option is
enabled. If pipefail is enabled, the pipeline's return status is the value of the last (rightmost)
command to exit with a non-zero status, or zero if all commands exit successfully. If the reserved word
! precedes a pipeline, the exit status of that pipeline is the logical negation of the exit status as
described above. The shell waits for all commands in the pipeline to terminate before returning a value.
If the time reserved word precedes a pipeline, the elapsed as well as user and system time consumed by
its execution are reported when the pipeline terminates. The -p option changes the output format to that
specified by POSIX. When the shell is in posix mode, it does not recognize time as a reserved word if
the next token begins with a `-'. The TIMEFORMAT variable may be set to a format string that specifies
how the timing information should be displayed; see the description of TIMEFORMAT under Shell Variables
When the shell is in posix mode, time may be followed by a newline. In this case, the shell displays the
total user and system time consumed by the shell and its children. The TIMEFORMAT variable may be used
to specify the format of the time information.
Each command in a pipeline is executed as a separate process (i.e., in a subshell).
output the last part of files
output the last K lines, instead of the last 10; or use -n +K to output lines starting with the
remove sections from each line of files
do not print lines not containing delimiters
select only these fields; also print any line that contains no delimiter character, unless the -s
option is specified
build and execute command lines from standard input
Replace occurrences of replace-str in the initial-arguments with names read from standard input.
Also, unquoted blanks do not terminate input items; instead the separator is the newline
character. Implies -x and -L 1.
This manual page documents the GNU version of xargs. xargs reads items from the standard input,
delimited by blanks (which can be protected with double or single quotes or a backslash) or newlines, and
executes the command (default is /bin/echo) one or more times with any initial-arguments followed by
items read from standard input. Blank lines on the standard input are ignored.
Use at most max-chars characters per command line, including the command and initial-arguments and
the terminating nulls at the ends of the argument strings. The largest allowed value is system-
dependent, and is calculated as the argument length limit for exec, less the size of your
environment, less 2048 bytes of headroom. If this value is more than 128KiB, 128Kib is used as
the default value; otherwise, the default value is the maximum. 1KiB is 1024 bytes.