export Cheatsheet
Quick reference for exporting shell variables and functions to child processes with export in Bash
The `export` builtin marks shell variables and functions so child processes can inherit them. This cheatsheet covers variable export, function export, removing the export property, and common shell-session patterns.
Basic Syntax
Core export command forms in Bash.
| Command | Description |
|---|---|
export VAR=value | Create and export a variable |
export VAR | Export an existing shell variable |
export -p | List all exported variables |
export -n VAR | Remove the export property |
help export | Show Bash help for export |
Export Variables
Use export to pass variables to child processes.
| Command | Description |
|---|---|
export APP_ENV=production | Export one variable |
PORT=8080; export PORT | Define first, export later |
export PATH="$HOME/bin:$PATH" | Extend PATH |
export EDITOR=nano | Set a default editor |
export LANG=en_US.UTF-8 | Set a locale variable |
Export for One Shell Session
These changes last only in the current shell session unless you save them in a startup file.
| Command | Description |
|---|---|
export DEBUG=1 | Enable a debug variable for the current session |
export API_URL=https://api.example.com | Set an application endpoint |
export PATH="$HOME/.local/bin:$PATH" | Add a per-user bin directory |
echo "$DEBUG" | Verify that the exported variable is set |
bash -c 'echo "$DEBUG"' | Confirm the child shell inherits the variable |
Export Functions
Bash can export functions to child Bash shells.
| Command | Description |
|---|---|
greet() { echo "Hello"; } | Define a shell function |
export -f greet | Export a function |
bash -c 'greet' | Run the exported function in a child shell |
export -nf greet | Remove the export property from a function |
Remove or Reset Exports
Use these commands when you no longer want a variable inherited.
| Command | Description |
|---|---|
export -n VAR | Keep the variable, but stop exporting it |
unset VAR | Remove the variable completely |
unset -f greet | Remove a shell function |
export -n PATH | Stop exporting PATH in the current shell |
| `env | grep ‘^VAR='` |
Make Variables Persistent
Add export lines to shell startup files when you want them loaded automatically.
| File | Use |
|---|---|
~/.bashrc | Interactive non-login Bash shells |
~/.bash_profile | Login Bash shells |
/etc/environment | System-wide environment variables |
/etc/profile | System-wide shell startup logic |
source ~/.bashrc | Reload the current shell after editing |
Troubleshooting
Quick checks for common export problems.
| Issue | Check |
|---|---|
| A child process cannot see the variable | Confirm you used export VAR or export VAR=value |
| The variable disappears in a new terminal | Add the export line to ~/.bashrc or another startup file |
| A function is missing in a child shell | Export it with export -f name and use Bash as the child shell |
The shell still sees the variable after export -n | export -n removes inheritance only; use unset to remove the variable completely |
| The variable is set but a command ignores it | Check whether the program reads that variable or expects a config file instead |
Related Guides
Use these guides for broader shell and environment-variable workflows.
| Guide | Description |
|---|---|
| export Command in Linux | Full guide to export options and examples |
| How to Set and List Environment Variables in Linux | Broader environment-variable overview |
| env cheatsheet | Inspect and override environment variables |
| Bash cheatsheet | Quick reference for Bash syntax and shell behavior |