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https://github.com/leahneukirchen/xe

simple xargs and apply replacement
https://github.com/leahneukirchen/xe

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simple xargs and apply replacement

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README 

        
XE(1)                       General Commands Manual                      XE(1)



NAME

     xe – execute a command for every argument



SYNOPSIS

     xe [-0FLRnqv] [-I replace-arg] [-N maxargs] [-j maxjobs] command ...

     xe [flags ...] -p pattern command ... [+ pattern command ...]...

     xe [flags ...] -f argfile command ...

     xe [flags ...] -s shellscript

     xe [flags ...] -a command ... -- args ...

     xe [flags ...] -A argsep command ... argsep args ...



DESCRIPTION

     The xe utility constructs command lines from specified arguments,

     combining some of the best features of xargs(1) and apply(1).



     xe means “execute for every ...”.



     xe supports different methods to specify arguments to commands:



     command ...

             By default, arguments - separated by newlines - are read from the

             standard input.  The resulting command is constructed from the

             command line parameters, replacing replace-arg with the read

             argument, and is executed with execvp(3).



             In this mode, no shell is involved and replace-arg must appear as

             a word on its own, i.e.  ‘foo {} bar’ will work, but ‘foo{} bar’

             will not, where {} is the default value for replace-arg.



             If no argument is specified, the default is ‘printf %s\n’.



     -f argfile

             Read arguments from argfile, instead of the standard input.



             This does not close the standard input for execution, it is

             passed to the forked process.



     -s shellscript

             In this mode, the single parameter shellscript is executed using

             sh -c.  In the script, the specified arguments can be accessed

             using $1, $2, ...



             For example:

                   echo 'a\nb' | xe -N2 -s 'echo $2 $1'



     -a command ... -- args ...

             In this mode, everything after -- is passed as args to command.



     -A argsep command ... argsep args ...

             Same as -a, but the custom argument separator argsep is used to

             distinguish between command and its args.



     The options are as follows:



     -0      Input arguments are separated by NUL bytes (instead of newlines,

             which is the default).



     -F      Fatal: stop and exit when a command execution fails.



     -L      Run the resulting commands with line-buffered output; lines from

             two jobs will not interleave.  When used twice, or with -vv, also

             prefix each line with the number of the job (see ENVIRONMENT) in

             such a manner that the output can be piped to ‘sort -snk1’ to

             group it.



     -R      Return with status 122 when no arguments have been specified

             (instead of 0, the default).  xe never executes a command when no

             arguments are specified.



     -n      Dry run: don't run the resulting commands, just print them.



     -q      Quiet mode: redirect standard output and standard error of

             commands to /dev/null.



     -v      Verbose: print commands to standard error before running them.

             When used twice, also print job id and exit status for each

             command.



     -p      Enable make(1)-style percent rules.  The first argument of

             command ... is regarded as a pattern, see PERCENT RULES below.

             Patterns without a slash (or ‘**’) are matched against the

             basenames only.



             Multiple runs of patterns and commands are separated by ‘+’.

             Only the first matching percent rule is executed; in case no

             pattern matches, no command is run.



     -I replace-arg

             Replace first occurrence of replace-arg (default: {}) in the

             resulting command with the argument(s).  Pass an empty

             replace-arg to disable the replace function.  Contrary to

             xargs(1) this will expand into multiple arguments when needed.



     -N maxargs

             Pass up to maxargs arguments to each command (default: 1).

             Using -N0 will pass as many arguments as possible.



     -j maxjobs

             Run up to maxjobs processes concurrently.  Using -j0 will run as

             many processes as there are CPU cores running.  If maxjobs ends

             with an ‘x’, it is regarded as a multiplier of the number of

             running CPU cores (rounded down, but using at least one core).



PERCENT RULES

     The percent rules of xe are similar to the globs of sh(1) or fnmatch(3):

     ‘?’ matches a single character that is not ‘/’.  ‘/’ matches one or

     multiple ‘/’ in the string.  ‘*’ matches zero or more characters, but

     never ‘/’.  ‘**’ matches zero or more characters, including ‘/’.  Note

     that all of these also match leading dots in file names.



     ‘{a,b,c}’ matches either a, b or c.  ‘[abc]’ matches one of the

     characters abc (but never ‘/’).  ‘[!abc]’ matches all characters but abc.

     Alternatively, ‘[^abc]’ can be used too.  ‘[a-c]’ matches any character

     in the range between a and c inclusive.  In character ranges, characters

     can be escaped using a backslash.



     In the pattern, a single occurrence of ‘%’ matches one or more

     characters, and replaces the first occurrence of ‘%’ with the matched

     string in the remaining arguments, which are then used as the command to

     be executed.



ENVIRONMENT

     The environment variable ITER is passed to the child process and

     incremented on each command execution.



EXIT STATUS

     xe follows the convention of GNU and OpenBSD xargs:

     0       on success

     123     if any invocation of the command exited with status 1 to 254.

     124     if the command exited with status 255

     125     if the command was killed by a signal

     126     if the command cannot be run

     127     if the command was not found

     1       if some other error occurred



     Additionally, 122 is returned when -R was passed and the command was

     never executed.



EXAMPLES

     Compress all .c files in the current directory, using all CPU cores:

           xe -a -j0 gzip -- *.c

     Remove all empty files, using lr(1):

           lr -U -t 'size == 0' | xe -N0 rm

     Convert .mp3 to .ogg, using all CPU cores:

           xe -a -j0 -s 'ffmpeg -i "${1}" "${1%.mp3}.ogg"' -- *.mp3

     Same, using percent rules:

           xe -a -j0 -p %.mp3 ffmpeg -i %.mp3 %.ogg -- *.mp3

     Similar, but hiding output of ffmpeg, instead showing spawned jobs:

           xe -ap -j0 -vvq '%.{m4a,ogg,opus}' ffmpeg -y -i {} out/%.mp3 -- *



SEE ALSO

     apply(1), parallel(1), xapply(1), xargs(1)



AUTHORS

     Leah Neukirchen 



LICENSE

     xe is in the public domain.



     To the extent possible under law, the creator of this work has waived all

     copyright and related or neighboring rights to this work.



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



Void Linux                      August 1, 2023                      Void Linux