Developer(s) GNU Project Operating system | Written in Perl Type Utility | |
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Stable release 20170222 / February 22, 2017; 14 days ago (2017-02-22) Repository git.savannah.gnu.org/cgit/parallel.git | ||
GNU parallel is a command-line driven utility for Linux and other Unix-like operating systems which allows the user to execute shell scripts in parallel. GNU parallel is free software, written by Ole Tange in Perl. It is available under the terms of GPLv3.
Contents
Usage
The most common usage is to replace the shell loop, for example
to the form of
where the file list contains arguments for do_something and where process_output may be empty.
Scripts using parallel are often easier to read than scripts using pexec.
The program parallel features also
By default, parallel runs as many jobs in parallel as there are CPU cores.
Examples
The above is the parallel equivalent to:
This searches in all files in the current directory and its subdirectories whose name end in .foo for occurrences of the string bar. The parallel command will work as expected unless a file name contains a newline. In order to avoid this limitation one may use:
The above command uses the null character to delimit file names.
The above command uses {} to tell parallel to replace {} with the argument list.
The command above does the same as:
however, the former command which uses find/parallel/cp is more resource efficient and will not halt with an error if the expansion of *.ogg is too large for the shell.