DOKK / manpages / debian 12 / env2 / env2.1.en
ENV2(1) User Contributed Perl Documentation ENV2(1)

env2 - Converts environment variables to various script languages.


env2 --save [FILE]

env2 # displays help

Do you prefer running bash while the rest of the team runs tcsh? Or perhaps you learned csh and the system administrators only know ksh. What happens when they (or you) supply an initialization script to source? If any of these situations sounds familiar, then this may be the script for you.

env2 takes shell scripts of one flavor in and spits out scripts effectively equivalent in another dialect. We say "effectively equivalent" because it does not translate syntax such as if/else statements. Instead, the original (source) script is evaluated to determine what environment variables it modifies, and the effective values of those variables are simply expressed in the syntax of the destination script's dialect. Typically, this is all you really need for scripts that modify the environment.

NOTE: If you need to the conditionals and for-loops to be used for different situations (e.g. different host architectures), then simply use this script repeatedly as needed.

Future extensions may include aliases or <functions>. Supported languages currently include: bash, csh, ksh, modulecmd, perl, plist, sh, tclsh, tcsh, vim, yaml, and zsh.

NOTE: The file version is identified by an internally computed SHA1 hash similar to the way git does versioning. If you get a warning message about inconsistent hash, it means that somebody modified the file without updating the $SHA variable.

Include all variables rather than just those that changed. See -diff.
Resets the ignore list to almost completely empty except for the generally dangerous environment list.

See -ignore, -reset, and -unsafe_clear.

Only include those variables whose values are different as a result of sourcing the specified input script. This is the default action.
The dialect to translate from. If not present, then the input file is examined for a #! line. If that fails, the SHELL environment variable is examined. If that fails, we default to bash (Hey, I had to choose something, and bash is the default Linux shell of choice).
This built-in documentation. Written in POD so that you can also have it in HTML, PDF, RTF, plain text or as a man page.
Comma separated list of variables to ignore. By default, env2 starts with the list set to


See also -clear, -reset and -unsafe_clear.

Lists variables that will be ignored. Useful if you are uncertain and want to clarify things before proceeding.
Specifies a FILE to save the results in. By default results are sent to STDOUT. If you leave off the FILE, the filename will be "env2."$SHELL.
Specifies a file that contains the starting environment. Defaults to ".env2profile". Searches for the file in the current directory or $HOME if path not specified.
Resets the ignore list to a minimum set.

See also -clear, -ignore and -unsafe_clear.

Saves the environment in a perl format. By default saves to Internally, this option is invoked as part of the conversion process and saves an intermediate file to /tmp/env2.$$.pl.
Displays the SHA1 version identifier. Use this to see if script has been modified since last updated.
The dialect to translate to. If not supplied, the SHELL environment variable is examined. If that fails, we default to bash (Hey, I had to choose something, and bash is the default Linux shell of choice).
Ensure that each path variable specified in PATHLIST contains a unique colon separated list. Default is to apply this to common path variables:

Resets the ignore list to completely empty. This is potentially dangerous because allows inclusion of dangerous environment variables that the user should not touch. These dangerous variables can have an adverse affect on operation of UNIX.

See also -clear, -ignore and -reset.

Display version of script.

ENV2 environment variable contains default command-line arguments if defined.

To support YAML, this script uses the CPAN YAML module.

 # Simple conversion
 env2 -from ksh -to csh -o setup.csh setup.ksh
 # Create a modules cmd for a new xyz tool version 1.0
 env2 -from sh -to modulecmd -o $MDLDIR/1.0 $TOOL_SETUP
 # Dynamically use a script for another shell to set environment
 eval `env2 -from ksh -to $SHELL -o setup.csh setup.ksh`

env2 is copyright (C) 2003-2008 David C Black. All rights reserved. This code may is hereby made available under Apache 2.0 licensing.

David C. Black <>

2018-02-18 perl v5.26.1