Master the Linux export Command: Beginner’s Guide to Environment Variables

The export command in Bash marks variables so that they are passed to child processes, allowing administrators to configure environment parameters without restarting the session.

Displaying All Exported Variables

Running export without arguments lists every exported variable and its value.

linuxmi@linuxmi:~$ export

Finding a Specific Variable

You can pipe the output to grep to locate a particular variable.

linuxmi@linuxmi:~$ export LINUXMI="Welcome to linuxmi.com"
linuxmi@linuxmi:~$ export | grep -i linuxmi

Displaying Current Shell Exported Variables

The -p flag prints the list of exported variables in a reusable format.

linuxmi@linuxmi:~$ export -p

Exporting a New Variable

Assign a value and export it in one step, then verify with grep.

linuxmi@linuxmi:~$ export EDITOR=/usr/bin/gedit
linuxmi@linuxmi:~$ export | grep -i EDITOR

Exporting a Function

Use the -f option to export a shell function, making it available to subshells.

linuxmi@linuxmi:~$ test () { echo "Test Function"; }
linuxmi@linuxmi:~$ export -f test
linuxmi@linuxmi:~$ bash
Test Function
linuxmi@linuxmi:~$ test
Test Function

Persisting Variables Across Sessions

Append an export statement to .bashrc (or another profile file) to set the variable each time a new shell starts.

linuxmi@linuxmi:~$ echo export PATH="/snap/bin/lxd:$PATH" >> .bashrc

After editing, the new PATH will be applied on the next login or when the profile is sourced.

Conclusion

The export command is a simple yet powerful tool for configuring environment parameters in Linux. By mastering its basic options—listing variables, exporting specific values, exporting functions, and persisting settings—you can efficiently manage your shell environment.