Environment variables (env-vars) are used to save system-wide value and those values can be accessed later by the system itself, the user, processes or applications. Each Operative System has its own way to create environment variables, in this article we will see how to do it for MacOS.
View all the Environments Variables
In MacOS we can view all the environment variable values by using the command printenv
agamboa% printenv PATH=/Users/agamboa/.nvm/versions/node/v12.8.0/bin:/usr/local/opt/postgresql@9.5/bin:/Users/agamboa/.jenv/shims:/usr/local/opt/gradle@6/bin:/usr/local/opt/awscli@1/bin:/usr/local/opt/awscli@1/bin:/usr/local/opt/openjdk@8/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/MacGPG2/bin SHELL=/bin/zsh TERM=xterm-256color USER=agamboa TMPDIR=/var/folders/7t/0bw1wkx14bb5tq783t7lx_gw0000gp/T/ COMMAND_MODE=unix2003 LOGIN_SHELL=1
View a specific Environment Variable
To view the value for a specific environment variable it’s possible with echo $<env-var name>
% echo $PATH /Users/agamboa/.nvm/versions/node/v12.8.0/bin:/usr/local/opt/postgresql@9.5/bin:/Users/agamboa/.jenv/shims:/usr/local/opt/gradle@6/bin:/usr/local/opt/awscli@1/bin:/usr/local/opt/awscli@1/bin:/usr/local/opt/openjdk@8/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/MacGPG2/bin
Set an Environment Variable
There are two ways to set an environment variable, temporarily and permanently. A temporary environment variable is one that is only accessible during the current session of the terminal, once the terminal is closed the env-var value will be removed. We can use the command export <EnvVarName>=<EnvVarValue> .
% export JAVA_HOME="/Library/Java/JavaVirtualMachines/jdk-16.jdk/Contents/Home"
In order to set an environment variable permanently, without requiring to set it every time the terminal is opened. First it’s required to know what is the shell type in our MacOS, we have bash and zsh as possible types.
In case the shell type is bash , then, the env-vars should be added to the .bashrc or the .bash_profile files. In the case zsh is the shell type, then the file is .zshrc . So, let’s add the a new line in the corresponding file.
export JAVA_HOME="/Library/Java/JavaVirtualMachines/jdk-16.jdk/Contents/Home"
Once the file is saved, we can close the terminal and open it again. From now on, the env-var will be set automatically. Another way without closing the terminal is to run. source <shell-file> .
% source ~/.zshrc
Conclusion
We have seen how to view and set up environment variables in MacOS, this should make it easier for you to configure software packages in the future.