Master shell configuration and environment variables. Learn to customize your shell with aliases, manage PATH, set environment variables, and configure startup files like .bashrc and .zshrc.

Learning Objectives

View and set environment variables

Understand and modify PATH

Create command aliases for efficiency

Configure shell startup files (.bashrc, .zshrc)

Make configuration changes persistent

Step 1

View environment variables

See what environment variables are currently set.

Commands to Run

env

printenv

echo $HOME

echo $USER

echo $SHELL

echo $PATH

What This Does

Environment variables are key-value pairs available to all programs. env/printenv show all variables. $HOME is your home directory. $USER is username. $SHELL is your shell. $PATH lists directories searched for commands.

Expected Outcome

env shows many variables. echo $HOME shows /home/username or /Users/username. $USER shows your username. $SHELL shows /bin/bash or /bin/zsh. $PATH shows colon-separated directories.

Pro Tips

1
env and printenv do the same thing
2
$ prefix accesses variable value: $HOME
3
Environment variables are UPPERCASE by convention
4
$HOME = your home directory
5
$USER = your username
6
$PWD = current directory
7
$PATH = where shell looks for commands

Common Mistakes to Avoid

⚠️Forgetting $ when accessing variables: echo HOME (wrong!) vs echo $HOME
⚠️Not understanding PATH determines which commands are found

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203 — Environment Variables & Configuration