Shell configuration

Getting started
Shell
Configuration
Dotfiles
Homebrew
Aliases
Environment variables

Customize your terminal with dotfiles, environment variables, aliases, and Homebrew packages. Learn how your shell reads configuration files and how to make changes that persist.

Published

Friday, February 6, 2026

Modified

Wednesday, February 11, 2026

Overview

Every time you open a terminal, your shell reads a set of configuration files before showing you a prompt. These files control how the shell behaves — what shortcuts are available, which programs it can find, and how the prompt looks. This tutorial explains how to edit those files, set environment variables, create aliases, and install a full set of recommended tools with Homebrew.

Prerequisites: Working with the filesystem

What are dotfiles?

In the previous tutorial you learned that are hidden files whose names start with a period. Many of the most important dotfiles are configuration files — plain text files that programs read at startup to learn your preferences.

Common dotfiles you will encounter:

File Used by
~/.zshrc Zsh shell configuration
~/.bashrc Bash shell configuration
~/.gitconfig Git settings (name, email, editor)
~/.config/ Directory for application configs

These files live in your home directory. Because they start with a dot, ls hides them unless you use ls -a.

Shell startup files

When you open a terminal, your shell runs a — a script that sets up your environment. Which file it reads depends on your shell:

Shell Startup file
Zsh (macOS default) ~/.zshrc
Bash (Linux/WSL default) ~/.bashrc
Note

You may also see files like ~/.zprofile or ~/.bash_profile. These run for login shells (the first shell started when you log in). For the purposes of this workgroup, focus on .zshrc or .bashrc — they handle interactive sessions, which is what you get when you open a terminal window.

Editing your config file

You can edit your shell config with any text editor. nano is a simple terminal-based editor that is available on all systems:

nano ~/.zshrc

Inside nano:

  • Type or paste text normally
  • Ctrl + O to save (then press Enter to confirm the filename)
  • Ctrl + X to exit

If you have Visual Studio Code installed, you can open the file in a graphical editor instead:

code ~/.zshrc
Tip

Before editing any config file, make a backup:

cp ~/.zshrc ~/.zshrc.backup

If something goes wrong, you can restore it:

cp ~/.zshrc.backup ~/.zshrc

Applying changes with source

After editing your config file, the changes do not take effect automatically — your current shell session already ran the old version at startup. You have two options:

  1. Open a new terminal window (it will read the updated file)
  2. Use the command to re-read the file in your current session:
source ~/.zshrc

For Bash users:

source ~/.bashrc

Environment variables

are key-value pairs that programs read to learn about your system and preferences. You can see all current environment variables with:

env

To see the value of a specific variable, use echo with a $ prefix:

echo $HOME
/Users/jane

Setting a variable

To create or change an environment variable for the current session:

MY_NAME="Jane"
echo $MY_NAME
Jane

This variable only exists in your current shell. To make it available to programs you launch from this shell, use :

export MY_NAME="Jane"

To make a variable persist across sessions, add the export line to your shell config file (~/.zshrc or ~/.bashrc).

The PATH variable

is the most important environment variable. It tells the shell where to look for programs when you type a command.

echo $PATH
/opt/homebrew/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin

The output is a list of directories separated by colons. When you type a command like brew, the shell searches these directories from left to right until it finds a program with that name. If the program is not in any of the PATH directories, you get a “command not found” error.

This is why the Homebrew installer asked you to add a line to your config file — it needed to put Homebrew’s directory (/opt/homebrew/bin on macOS, /home/linuxbrew/.linuxbrew/bin on Linux) into your PATH.

Adding a directory to PATH

To add a directory to PATH, add a line like this to your config file:

export PATH="/some/new/directory:$PATH"

The $PATH at the end preserves the existing directories. New directories go at the beginning so they are searched first.

If Homebrew is not working after installation, this is most likely the fix. Add the appropriate line for your system:

For Zsh on macOS:

echo 'eval "$(/opt/homebrew/bin/brew shellenv)"' >> ~/.zshrc

For Bash on Linux:

echo 'eval "$(/home/linuxbrew/.linuxbrew/bin/brew shellenv)"' >> ~/.bashrc

Then apply the change:

source ~/.zshrc   # or source ~/.bashrc

Other useful variables

Variable What it stores
HOME Your home directory path
EDITOR Your preferred text editor (e.g. nano, vim, code)
SHELL The path to your current shell program
USER Your username

To set a default editor, add this to your config file:

export EDITOR="nano"

Aliases

An is a shortcut — a custom name for a command or series of commands. You define aliases in your shell config file so they are available every session.

Creating an alias

The syntax is:

alias shortcut='command'

For example, a shortcut to go up one directory:

alias ..='cd ..'

Now typing .. at the prompt runs cd ...

Temporary vs persistent aliases

If you type an alias directly at the prompt, it lasts only until you close the terminal. To make it permanent, add the alias line to ~/.zshrc (or ~/.bashrc) and run source to activate it.

Alias chaining

An alias can reference another alias. For example, suppose you create a base alias for eza (a modern replacement for ls) with colorized output:

alias ls='eza --icons=auto --color=auto'

You can then build on it:

alias la='ls -a'           # all files, including hidden
alias ll='ls -l'           # long format with details
alias lla='ls -la'         # both hidden and detailed

Since la uses the ls alias, it inherits the --icons=auto --color=auto flags automatically.

Practical alias examples

Navigation:

alias ..='cd ..'
alias ...='cd ../..'
alias c='clear'

Safety (ask before overwriting or deleting):

alias cp='cp -i'
alias mv='mv -i'
alias rm='rm -i'

Tool replacements (once installed via Homebrew):

alias cat='bat'
alias ls='eza --icons=auto --color=auto'

Using aliases is highly individualized. As you use the CLI more, you will develop your own collection of shortcuts tuned to your workflow.

Working with Homebrew

You installed in the CLI fundamentals tutorial. Now let’s learn how to use it effectively.

Formulae vs casks

Homebrew distinguishes two types of packages:

  • Formulae — command-line tools and libraries installed in the terminal (e.g. python, git, eza)
  • Casks — desktop applications with a graphical interface (e.g. visual-studio-code, iterm2)

Common brew commands

Install a formula:

brew install <package_name>

Install a cask (desktop app):

brew install --cask <package_name>

Update Homebrew and upgrade all installed packages:

brew update && brew upgrade
Tip

Run brew update && brew upgrade every few weeks to keep your tools current.

Search for a package:

brew search <query>

View details about a package:

brew info <package_name>

List everything you have installed:

brew list

Uninstall a package:

brew uninstall <package_name>

Configuring installed tools

Some packages need a line in your shell config to activate. Here are the common ones.

zoxide

Add to your config file:

eval "$(zoxide init zsh)"    # for Zsh
eval "$(zoxide init bash)"   # for Bash

After sourcing, you can use z to jump to directories you have visited before:

z Documents    # jumps to ~/Documents (or whichever "Documents" you visit most)

thefuck

Add to your config file:

eval "$(thefuck --alias)"

Now, after a mistyped command, type fuck and it will suggest the correction.

eza aliases

To replace ls with eza everywhere, add these aliases:

alias ls='eza --icons=auto --color=auto'
alias la='ls --almost-all'
alias ll='ls --long --time-style=relative --ignore-glob=.git'
alias lla='la --long --time-style=relative --ignore-glob=.git'

bat as a pager

To use bat for manual pages and as the default pager:

export MANPAGER="sh -c 'col -bx | bat -l man -p'"
export PAGER="bat"

Worked example

Here is a complete block you could add to the end of your ~/.zshrc (or ~/.bashrc, replacing zsh with bash in the zoxide line):

# Tool integrations
eval "$(zoxide init zsh)"
eval "$(thefuck --alias)"

# Enhanced defaults
alias ls='eza --icons=auto --color=auto'
alias la='ls --almost-all'
alias ll='ls --long --time-style=relative --ignore-glob=.git'
alias cat='bat'

# Navigation shortcuts
alias ..='cd ..'
alias ...='cd ../..'
alias c='clear'

# Safety
alias cp='cp -i'
alias mv='mv -i'
alias rm='rm -i'

# Pager
export MANPAGER="sh -c 'col -bx | bat -l man -p'"
export PAGER="bat"

After adding this block, apply it:

source ~/.zshrc

Then test a few commands:

ls              # should show icons and color
z ~             # should jump to home
tldr ls         # should show a simplified help page

The setup script

If you prefer to automate the entire process described in this tutorial, the workgroup provides a setup script that installs all recommended packages, configures Git, and appends shell integrations to your config file.

Run it directly:

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/wfu-agentic-ai/workgroup/main/setup.sh)"

Or preview what it would do without making changes:

curl -fsSL https://raw.githubusercontent.com/wfu-agentic-ai/workgroup/main/setup.sh | bash -s -- --dry-run
Note

If you followed this tutorial manually and installed everything yourself, you already have what the script provides. The script is most useful for setting up a new machine quickly or helping someone who wants to skip the step-by-step process.

Summary

Concept Key command / file
Shell config file ~/.zshrc (Zsh) or ~/.bashrc (Bash)
Edit config nano ~/.zshrc or code ~/.zshrc
Apply changes source ~/.zshrc
Set environment variable export VARIABLE=value
Create alias alias shortcut='command'
Install package brew install <name>
Update packages brew update && brew upgrade
Backup config cp ~/.zshrc ~/.zshrc.backup

Next tutorial: Git fundamentals