Environment Switcher

• Author: Adam Bolte
• Contact: [email protected]
• Copyright: GPL3+

This is a small Bash script that gives the user the ability to quickly source profiles of environment variables. This is particularly useful for OpenStack, AWS and other IaaS providers which require various environment variables in order to function with different accounts.

Project page

https://github.com/sitepoint/envswitch

Requirements

• GNU Bash
• GNU core utilities
• GNU sed

These are the dependencies that were tested, and should be available on almost any desktop or server GNU/Linux distribution.

Environment Switcher has also been reported to work with Zsh on MacOS.

Setup

Place the envswitch script somewhere in your path and ensure it has executable permissions configured. Next, in your login shell (eg. ~/.bashrc for GNU Bash, ~/.zshrc for Z shell) file add the following line:

eval "$(envswitch -i)"

Profile configuration

Upon first execution of envswitch, the directory ${HOME}/.config/envswitch will be created. Install environment variables into a file under this directory with a .conf extension. eg.

somevar="test1"
# This is a comment.
anothervar="${somevar}"
numbervar=123

Note the name of the configuration file (minus the .conf extension) should not match the name of an existing shell function. If in doubt, check the output of declare -F.

Usage

Listing and loading profiles

Profiles exist as local shell functions, which can be called any time just by typing the name.

A list of available profiles can be viewed like so:

envswitch -l

Note that the shell functions will source the associated profile file when called, as profile contents are not automatically imported. This is done to prevent declare -f from also exposing environment variables.

Once a profile has been loaded, the shell prompt ($PS1) should be updated to include the profile name. If this is undesirable, replace -i with -I in the login shell file to prevent it from happening.

Show loaded environment variables

The loaded profile can be printed to standard output with the following command:

envswitch -s

This will effectively just print the unmodified profile to standard output like so:

somevar="test1"
# This is a comment.
anothervar="${somevar}"
numbervar=123

There is also the -e flag which is occasionally useful:

envswitch -e

This functions almost the same as -s, except all environment variables will be printed with an ``export `` prefixed to each one, making it convenient to export some or all environment variables quickly for use on a different machine that does not have envswitch installed or configured. eg.

export somevar="test1"
# This is a comment.
export anothervar="${somevar}"
export numbervar=123

Help

A summary of all possible arguments can also be shown:

envswitch -h

Unloading a profile

To clear all environment variables from the shell and unload the current profile:

envreset

Note that when switching profiles, it is not necessary to call envreset first. Any currently loaded profile will be unloaded automatically before the new profile is imported.

Issues

If you encounter any bugs or would like to propose a new feature, feel free to open an issue on GitHub, however please be patent with a response.

Likewise, pull requests are also welcome.