export Command in Linux: Environment Variables

Quick take: The export command marks a shell variable as an environment variable so child processes inherit it: export PATH=$PATH:/opt/bin. Without export, a variable stays local to the current shell.

Introduction

Variables in the shell come in two kinds: ordinary shell variables, visible only to the current shell, and environment variables, inherited by every program the shell launches. The export command promotes a variable to the environment, which is how you configure programs through variables like PATH, EDITOR, and application-specific settings.

Syntax

The basic syntax of the export command is:

export NAME=VALUE
export NAME

Common Options and Parameters

The most useful options and parameters for the export command:

Practical Examples

Real export commands you can run today:

# Set and export a variable
export EDITOR=vim
# Add a directory to PATH
export PATH=$PATH:/opt/myapp/bin
# Export an existing variable
MYVAR=hello; export MYVAR
# List exported variables
export -p
# Show the whole environment
printenv
# Make it permanent (add to ~/.bashrc)
echo 'export EDITOR=vim' >> ~/.bashrc

Tips and Best Practices

• A variable set without export is visible only to the current shell; child programs will not see it until you export it.
• To make an environment variable permanent, add the export line to ~/.bashrc (per user) or /etc/environment (system-wide).
• When extending PATH, always include the existing value (export PATH=$PATH:/new) so you do not wipe it out.

Final Thoughts

export is how variables reach the programs you run — promoting a shell variable into the environment that child processes inherit. Use it for PATH, editor preferences, and app configuration, always preserving existing values when appending. Add the lines to ~/.bashrc to make them stick, and use printenv to inspect the result.