ENV_PARALLEL(1) parallel ENV_PARALLEL(1)

env_parallel - export environment to GNU parallel

env_parallel [--record-env|--session|--end-session] [options for GNU Parallel]

env_parallel is a shell function that exports the current environment to GNU parallel.

If the shell function is not loaded, a dummy script will be run instead that explains how to install the function.

env_parallel is 100 ms slower at startup than pure GNU parallel, and takes up to 30% longer to start a job (typically 15 ms).

Due to the problem with environment space (see below) the recommended usage is either:

# Do --record-env into $PARALLEL_IGNORED_NAMES
env_parallel --session

# Define whatever you want to use
alias myalias=echo
myvar=it
myfunc() { myalias $1 $myvar works.; }

# env_parallel will not export names in $PARALLEL_IGNORED_NAMES
env_parallel -S localhost myfunc ::: Yay,

Or:

# Record the "clean" environment (this only needs to be run once)
env_parallel --record-env

# Optionally edit ~/.parallel/ignored_vars (only needed once)

# Define whatever you want to use
alias myalias=echo
myvar=it
myfunc() { myalias $1 $myvar works.; }

# Use --env _ to only transfer the names not in the "empty" environment
env_parallel --env _ -S localhost myfunc ::: Yay,

In csh --session is not supported:

# Record the "clean" environment (this only needs to be run once)
env_parallel --record-env

# Optionally edit ~/.parallel/ignored_vars (only needed once)

# Define whatever you want to use
alias myalias 'echo \!* $myvar works.'
set myvar=it

# Use --env _ to only transfer the names not in the "empty" environment
env_parallel --env _ -S localhost myalias ::: Yay,

By default env_parallel will export all environment variables, arrays, aliases, functions and shell options (see details for the individual shells below).

But this only works if the size of the current environment is smaller than the maximal length of a command and smaller than half of the max if running remotely. E.g. The max size of Bash's command is 128 KB, so env_parallel will fail if 'set | wc -c' is bigger than 128 KB. Technically the limit is in execve(1) which IPC::open3 uses.

Bash completion functions are well-known for taking up well over 128 KB of environment space and the primary reason for causing env_parallel to fail.

Instead you can use --env to specify which variables, arrays, aliases and functions to export as this will only export those with the given name. Or follow the recommended usage in shown in DESCRIPTION.

Same as GNU parallel in addition to these:
--end-session
Undo last --session
--record-env
Record all names currently defined to be ignored every time running env_parallel in the future.
--session
Ignore all names currently defined. Aliases, variables, arrays, and functions currently defined will not be transferred.

But names defined after running parallel --session will be transferred.

This is only valid in the running shell, and can be undone with parallel --end-session.

You can run multiple --session inside each other:

env_parallel --session
var=not
# var is transferred
env_parallel -Slocalhost 'echo var is $var' ::: ignored
env_parallel --session
# var is not transferred
env_parallel -Slocalhost 'echo var is $var' ::: ignored
env_parallel --end-session
# var is transferred again
env_parallel -Slocalhost 'echo var is $var' ::: ignored

Installation

Put this in $HOME/.profile:

. `which env_parallel.ash`

E.g. by doing:

echo '. `which env_parallel.ash`' >> $HOME/.profile

Supported use

--env is supported to export only the variable, or alias with the given name. Multiple --envs can be given.

--session is supported.

aliases
alias myecho='echo aliases'
env_parallel myecho ::: work
env_parallel -S server myecho ::: work
env_parallel --env myecho myecho ::: work
env_parallel --env myecho -S server myecho ::: work

alias multiline='echo multiline
  echo aliases'
env_parallel multiline ::: work
env_parallel -S server multiline ::: work
env_parallel --env multiline multiline ::: work
env_parallel --env multiline -S server multiline ::: work
functions
ash cannot list defined functions - thus is not supported.
variables
myvar=variables
env_parallel echo '$myvar' ::: work
env_parallel -S server echo '$myvar' ::: work
env_parallel --env myvar echo '$myvar' ::: work
env_parallel --env myvar -S server echo '$myvar' ::: work
arrays
Arrays are not supported by Ash.

Installation

Put this in $HOME/.bashrc:

. `which env_parallel.bash`

E.g. by doing:

echo '. `which env_parallel.bash`' >> $HOME/.bashrc

Supported use

--env is supported to export only the variable, alias, function, or array with the given name. Multiple --envs can be given.

--session is supported.

aliases
alias myecho='echo aliases'
env_parallel myecho ::: work
env_parallel -S server myecho ::: work
env_parallel --env myecho myecho ::: work
env_parallel --env myecho -S server myecho ::: work

alias multiline='echo multiline
  echo aliases'
env_parallel 'multiline {};
  echo but only when followed by a newline' ::: work
env_parallel -S server 'multiline {};
  echo but only when followed by a newline' ::: work
env_parallel --env multiline 'multiline {};
  echo but only when followed by a newline' ::: work
env_parallel --env multiline -S server 'multiline {};
  echo but only when followed by a newline' ::: work
functions
myfunc() { echo functions $*; }
env_parallel myfunc ::: work
env_parallel -S server myfunc ::: work
env_parallel --env myfunc myfunc ::: work
env_parallel --env myfunc -S server myfunc ::: work
variables
myvar=variables
env_parallel echo '$myvar' ::: work
env_parallel -S server echo '$myvar' ::: work
env_parallel --env myvar echo '$myvar' ::: work
env_parallel --env myvar -S server echo '$myvar' ::: work
arrays
myarray=(arrays work, too)
env_parallel -k echo '${myarray[{}]}' ::: 0 1 2
env_parallel -k -S server echo '${myarray[{}]}' ::: 0 1 2
env_parallel -k --env myarray echo '${myarray[{}]}' ::: 0 1 2
env_parallel -k --env myarray -S server \
  echo '${myarray[{}]}' ::: 0 1 2

BUGS

Due to a bug in Bash, aliases containing newlines must be followed by a newline in the command.

env_parallel for csh breaks $PARALLEL, so do not use $PARALLEL.

Installation

Put this in $HOME/.cshrc:

source `which env_parallel.csh`

E.g. by doing:

echo 'source `which env_parallel.csh`' >> $HOME/.cshrc

Supported use

--env is supported to export only the variable, alias, or array with the given name. Multiple --envs can be given.

aliases
alias myecho 'echo aliases'
env_parallel myecho ::: work
env_parallel -S server myecho ::: work
env_parallel --env myecho myecho ::: work
env_parallel --env myecho -S server myecho ::: work
functions
Not supported by csh.
variables
set myvar=variables
env_parallel echo '$myvar' ::: work
env_parallel -S server echo '$myvar' ::: work
env_parallel --env myvar echo '$myvar' ::: work
env_parallel --env myvar -S server echo '$myvar' ::: work
arrays with no special chars
set myarray=(arrays work, too)
env_parallel -k echo \$'{myarray[{}]}' ::: 1 2 3
env_parallel -k -S server echo \$'{myarray[{}]}' ::: 1 2 3
env_parallel -k --env myarray echo \$'{myarray[{}]}' ::: 1 2 3
env_parallel -k --env myarray -S server \
  echo \$'{myarray[{}]}' ::: 1 2 3

Installation

Put this in $HOME/.profile:

. `which env_parallel.dash`

E.g. by doing:

echo '. `which env_parallel.dash`' >> $HOME/.profile

Supported use

--env is supported to export only the variable, or alias with the given name. Multiple --envs can be given.

--session is supported.

aliases
alias myecho='echo aliases'
env_parallel myecho ::: work
env_parallel -S server myecho ::: work
env_parallel --env myecho myecho ::: work
env_parallel --env myecho -S server myecho ::: work

alias multiline='echo multiline
  echo aliases'
env_parallel multiline ::: work
env_parallel -S server multiline ::: work
env_parallel --env multiline multiline ::: work
env_parallel --env multiline -S server multiline ::: work
functions
dash cannot list defined functions - thus is not supported.
variables
myvar=variables
env_parallel echo '$myvar' ::: work
env_parallel -S server echo '$myvar' ::: work
env_parallel --env myvar echo '$myvar' ::: work
env_parallel --env myvar -S server echo '$myvar' ::: work
arrays
dash does not support arrays.

Installation

Put this in $HOME/.config/fish/config.fish:

source (which env_parallel.fish)

E.g. by doing:

echo 'source (which env_parallel.fish)' \
  >> $HOME/.config/fish/config.fish

Supported use

--env is supported to export only the variable, alias, function, or array with the given name. Multiple --envs can be given.

--session is supported.

aliases
alias myecho 'echo aliases'
env_parallel myecho ::: work
env_parallel -S server myecho ::: work
env_parallel --env myecho myecho ::: work
env_parallel --env myecho -S server myecho ::: work
functions
function myfunc
  echo functions $argv
end
env_parallel myfunc ::: work
env_parallel -S server myfunc ::: work
env_parallel --env myfunc myfunc ::: work
env_parallel --env myfunc -S server myfunc ::: work
variables
set myvar variables
env_parallel echo '$myvar' ::: work
env_parallel -S server echo '$myvar' ::: work
env_parallel --env myvar echo '$myvar' ::: work
env_parallel --env myvar -S server echo '$myvar' ::: work
arrays
set myarray arrays work, too
env_parallel -k echo '$myarray[{}]' ::: 1 2 3
env_parallel -k -S server echo '$myarray[{}]' ::: 1 2 3
env_parallel -k --env myarray echo '$myarray[{}]' ::: 1 2 3
env_parallel -k --env myarray -S server \
  echo '$myarray[{}]' ::: 1 2 3

Installation

Put this in $HOME/.kshrc:

source `which env_parallel.ksh`

E.g. by doing:

echo 'source `which env_parallel.ksh`' >> $HOME/.kshrc

Supported use

--env is supported to export only the variable, alias, function, or array with the given name. Multiple --envs can be given.

--session is supported.

aliases
alias myecho='echo aliases'
env_parallel myecho ::: work
env_parallel -S server myecho ::: work
env_parallel --env myecho myecho ::: work
env_parallel --env myecho -S server myecho ::: work

alias multiline='echo multiline
  echo aliases'
env_parallel multiline ::: work
env_parallel -S server multiline ::: work
env_parallel --env multiline multiline ::: work
env_parallel --env multiline -S server multiline ::: work
functions
myfunc() { echo functions $*; }
env_parallel myfunc ::: work
env_parallel -S server myfunc ::: work
env_parallel --env myfunc myfunc ::: work
env_parallel --env myfunc -S server myfunc ::: work
variables
myvar=variables
env_parallel echo '$myvar' ::: work
env_parallel -S server echo '$myvar' ::: work
env_parallel --env myvar echo '$myvar' ::: work
env_parallel --env myvar -S server echo '$myvar' ::: work
arrays
myarray=(arrays work, too)
env_parallel -k echo '${myarray[{}]}' ::: 0 1 2
env_parallel -k -S server echo '${myarray[{}]}' ::: 0 1 2
env_parallel -k --env myarray echo '${myarray[{}]}' ::: 0 1 2
env_parallel -k --env myarray -S server \
  echo '${myarray[{}]}' ::: 0 1 2

Installation

Put this in $HOME/.mkshrc:

source `which env_parallel.mksh`

E.g. by doing:

echo 'source `which env_parallel.mksh`' >> $HOME/.mkshrc

Supported use

--env is supported to export only the variable, alias, function, or array with the given name. Multiple --envs can be given.

--session is supported.

aliases
alias myecho='echo aliases'
env_parallel myecho ::: work
env_parallel -S server myecho ::: work
env_parallel --env myecho myecho ::: work
env_parallel --env myecho -S server myecho ::: work

alias multiline='echo multiline
  echo aliases'
env_parallel multiline ::: work
env_parallel -S server multiline ::: work
env_parallel --env multiline multiline ::: work
env_parallel --env multiline -S server multiline ::: work
functions
myfunc() { echo functions $*; }
env_parallel myfunc ::: work
env_parallel -S server myfunc ::: work
env_parallel --env myfunc myfunc ::: work
env_parallel --env myfunc -S server myfunc ::: work
variables
myvar=variables
env_parallel echo '$myvar' ::: work
env_parallel -S server echo '$myvar' ::: work
env_parallel --env myvar echo '$myvar' ::: work
env_parallel --env myvar -S server echo '$myvar' ::: work
arrays
myarray=(arrays work, too)
env_parallel -k echo '${myarray[{}]}' ::: 0 1 2
env_parallel -k -S server echo '${myarray[{}]}' ::: 0 1 2
env_parallel -k --env myarray echo '${myarray[{}]}' ::: 0 1 2
env_parallel -k --env myarray -S server \
  echo '${myarray[{}]}' ::: 0 1 2

Installation

Put this in $HOME/.profile:

source `which env_parallel.pdksh`

E.g. by doing:

echo 'source `which env_parallel.pdksh`' >> $HOME/.profile

Supported use

--env is supported to export only the variable, alias, function, or array with the given name. Multiple --envs can be given.

--session is supported.

aliases
alias myecho="echo aliases";
env_parallel myecho ::: work;
env_parallel -S server myecho ::: work;
env_parallel --env myecho myecho ::: work;
env_parallel --env myecho -S server myecho ::: work
functions
myfunc() { echo functions $*; };
env_parallel myfunc ::: work;
env_parallel -S server myfunc ::: work;
env_parallel --env myfunc myfunc ::: work;
env_parallel --env myfunc -S server myfunc ::: work
variables
myvar=variables;
env_parallel echo "\$myvar" ::: work;
env_parallel -S server echo "\$myvar" ::: work;
env_parallel --env myvar echo "\$myvar" ::: work;
env_parallel --env myvar -S server echo "\$myvar" ::: work
arrays
myarray=(arrays work, too);
env_parallel -k echo "\${myarray[{}]}" ::: 0 1 2;
env_parallel -k -S server echo "\${myarray[{}]}" ::: 0 1 2;
env_parallel -k --env myarray echo "\${myarray[{}]}" ::: 0 1 2;
env_parallel -k --env myarray -S server \
  echo "\${myarray[{}]}" ::: 0 1 2

Installation

Put this in $HOME/.profile:

. `which env_parallel.sh`

E.g. by doing:

echo '. `which env_parallel.sh`' >> $HOME/.profile

Supported use

--env is supported to export only the variable, or alias with the given name. Multiple --envs can be given.

--session is supported.

aliases
sh does not support aliases.
functions
myfunc() { echo functions $*; }
env_parallel myfunc ::: work
env_parallel -S server myfunc ::: work
env_parallel --env myfunc myfunc ::: work
env_parallel --env myfunc -S server myfunc ::: work
variables
myvar=variables
env_parallel echo '$myvar' ::: work
env_parallel -S server echo '$myvar' ::: work
env_parallel --env myvar echo '$myvar' ::: work
env_parallel --env myvar -S server echo '$myvar' ::: work
arrays
sh does not support arrays.

env_parallel for tcsh breaks $PARALLEL, so do not use $PARALLEL.

Installation

Put this in $HOME/.tcshrc:

source `which env_parallel.tcsh`

E.g. by doing:

echo 'source `which env_parallel.tcsh`' >> $HOME/.tcshrc

Supported use

--env is supported to export only the variable, alias, or array with the given name. Multiple --envs can be given.

aliases
alias myecho 'echo aliases'
env_parallel myecho ::: work
env_parallel -S server myecho ::: work
env_parallel --env myecho myecho ::: work
env_parallel --env myecho -S server myecho ::: work
functions
Not supported by tcsh.
variables
set myvar=variables
env_parallel echo '$myvar' ::: work
env_parallel -S server echo '$myvar' ::: work
env_parallel --env myvar echo '$myvar' ::: work
env_parallel --env myvar -S server echo '$myvar' ::: work
arrays with no special chars
set myarray=(arrays work, too)
env_parallel -k echo \$'{myarray[{}]}' ::: 1 2 3
env_parallel -k -S server echo \$'{myarray[{}]}' ::: 1 2 3
env_parallel -k --env myarray echo \$'{myarray[{}]}' ::: 1 2 3
env_parallel -k --env myarray -S server \
  echo \$'{myarray[{}]}' ::: 1 2 3

Installation

Put this in $HOME/.zshrc:

. `which env_parallel.zsh`

E.g. by doing:

echo '. `which env_parallel.zsh`' >> $HOME/.zshenv

Supported use

--env is supported to export only the variable, alias, function, or array with the given name. Multiple --envs can be given.

--session is supported.

aliases
alias myecho='echo aliases'
env_parallel myecho ::: work
env_parallel -S server myecho ::: work
env_parallel --env myecho myecho ::: work
env_parallel --env myecho -S server myecho ::: work

alias multiline='echo multiline
  echo aliases'
env_parallel multiline ::: work
env_parallel -S server multiline ::: work
env_parallel --env multiline multiline ::: work
env_parallel --env multiline -S server multiline ::: work
functions
myfunc() { echo functions $*; }
env_parallel myfunc ::: work
env_parallel -S server myfunc ::: work
env_parallel --env myfunc myfunc ::: work
env_parallel --env myfunc -S server myfunc ::: work
variables
myvar=variables
env_parallel echo '$myvar' ::: work
env_parallel -S server echo '$myvar' ::: work
env_parallel --env myvar echo '$myvar' ::: work
env_parallel --env myvar -S server echo '$myvar' ::: work
arrays
myarray=(arrays work, too)
env_parallel -k echo '${myarray[{}]}' ::: 1 2 3
env_parallel -k -S server echo '${myarray[{}]}' ::: 1 2 3
env_parallel -k --env myarray echo '${myarray[{}]}' ::: 1 2 3
env_parallel -k --env myarray -S server \
  echo '${myarray[{}]}' ::: 1 2 3

Same as GNU parallel.

When using GNU env_parallel for a publication please cite:

O. Tange (2011): GNU Parallel - The Command-Line Power Tool, ;login: The USENIX Magazine, February 2011:42-47.

This helps funding further development; and it won't cost you a cent. If you pay 10000 EUR you should feel free to use GNU Parallel without citing.

Copyright (C) 2007-10-18 Ole Tange, http://ole.tange.dk

Copyright (C) 2008-2010 Ole Tange, http://ole.tange.dk

Copyright (C) 2010-2020 Ole Tange, http://ole.tange.dk and Free Software Foundation, Inc.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or at your option any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.

Permission is granted to copy, distribute and/or modify this documentation under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the file fdl.txt.

You are free:
to Share
to copy, distribute and transmit the work
to Remix
to adapt the work

Under the following conditions:

Attribution
You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work).
Share Alike
If you alter, transform, or build upon this work, you may distribute the resulting work only under the same, similar or a compatible license.

With the understanding that:

Waiver
Any of the above conditions can be waived if you get permission from the copyright holder.
Public Domain
Where the work or any of its elements is in the public domain under applicable law, that status is in no way affected by the license.
Other Rights
In no way are any of the following rights affected by the license:
  • Your fair dealing or fair use rights, or other applicable copyright exceptions and limitations;
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Notice
For any reuse or distribution, you must make clear to others the license terms of this work.

A copy of the full license is included in the file as cc-by-sa.txt.

env_parallel uses GNU parallel.

parallel(1), ash(1), bash(1), csh(1), dash(1), fish(1), ksh(1), pdksh(1) tcsh(1), zsh(1).
2020-01-27 20200122