xe

xe: simple xargs and apply replacement

xe is a new tool for constructing command lines from file listings or arguments, which includes the best features of xargs(1) and apply(1).

xe means “execute for every …”.

Benefits

Over xargs:

Sane defaults (behaves like xargs -d'\n' -I{} -n1 -r).
No weird parsing, arguments are separated linewise or by NUL byte.
Can also take arguments from command-line.
No shell involved unless -s is used.
{} replacing possible with multiple arguments.

Over apply:

Parallel mode.
Sane argument splitting.
Can use shell-syntax instead of escape characters.

Usage:

xe [-0FLRnv] [-I arg] [-N maxargs] [-j maxjobs] COMMAND...
   | -f ARGFILE COMMAND...
   | -s SHELLSCRIPT
   | -a COMMAND... -- ARGS...
   | -A ARGSEP COMMAND... ARGSEP ARGS...

-0: input filenames are separated by NUL bytes (default: newlines).
-F: fatal: stop after first failing command.
-L: run the commands with line-buffered output; lines from two jobs will not interleave.
-LL: prefix each line with the job id in such a manner that the output can be piped to sort -snk1 to group it by job.
-R: return with status 122 when no arguments have been passed.
-n: don’t run the commands, just print them.
-v: print commands to standard error before running them.
-vv: print job id and exit status for each command.
-I: replace occurrences of arg with the argument(s) (default: {}). Use an empty arg to disable the replace function.
-N: pass up to maxargs arguments to each COMMAND (default: 1). -N0 will pass as many arguments as possible.
-j: run up to maxjobs processes concurrently. -j0 will run as many processes as there are CPU cores running. -j2x will run twice as many processes as there are CPU cores running.
COMMAND...: default operation: each command line argument is passed as-is, {} is replaced by the argument (not with -N > 1).
-f ARGFILE: Read arguments from ARGFILE, do not close standard input.
-s SHELLSCRIPT: The argument SHELLSCRIPT is evaluated using /bin/sh with the arguments (up to -N) passed as $1, $2, $3… (this behaves as if /bin/sh -c SHELLSCRIPT - is passed as plain COMMAND).
-a: take arguments from commandline, starting after the first --.
-A: take arguments from commandline, starting after the first argsep.

If no argument is passed, default to “printf %s\n”.

The current iteration is passed as $ITER to the child process (increased on every exec()).

Return code

Like GNU and OpenBSD xargs:

0 on success
123 if any invocation of the command exited with status 1-125
124 if the command exited with status 255
125 if the command is killed by a signal
126 if the command cannot be run
127 if the command is not found
1 if some other error occurred.

Additionally, 122 is returned when -R is passed and no input/arguments were passed.

Installation

Use make all to build, make install to install relative to PREFIX (/usr/local by default). The DESTDIR convention is respected. You can also just copy the binary into your PATH.

Copyright

xe is in the public domain.

To the extent possible under law, Leah Neukirchen leah@vuxu.org has waived all copyright and related or neighboring rights to this work.

http://creativecommons.org/publicdomain/zero/1.0/