Just Enough CLI

The Command Line Interface essentials — basic commands, CLI editors, ZSH vs BASH, plugins and themes.

What this video covers

A shell is a program that runs commands — the ones you type into a terminal window. It’s also a small programming environment: Unix workflows lean on breaking tasks into small components and piping them together instead of clicking through a GUI. Every Unix shell (bash, zsh, the C shell) traces back to the Bourne shell (/bin/sh) from early Unix. This lesson covers why the CLI matters for data roles, how to set up a modern shell on Mac and Windows, and the core commands you’ll reach for constantly in day-to-day analytics and engineering work.

Hands-on labs

Key moments

• Why data people need the CLI — SSH into a VM, edit config files with nano/vim, run Git, drive AWS/Azure/GCP without the console, set up cron jobs, and automate scripts. Both engineers and analysts lean on it; it’s less common day-to-day for analysts but shows up constantly for engineers.
• Shell prompts — $ means a normal user, # means root/admin, and the C shell ends its prompt with %.
• Setting up Linux on Windows — install WSL (wsl --install from an admin CMD) to get a real Linux environment without dual-booting.
• Oh My Zsh on Mac — Mac has used zsh as the default shell since Catalina; installing Oh My Zsh adds themes and plugins, including zsh-autosuggestions (autocomplete) and zsh-syntax-highlighting.
• The essential commands — cat, ls, cp, mv, touch, rm, echo, cd, mkdir, rmdir, grep, less, pwd, diff, file, find/locate, head/tail, and sort.
• Wildcards and regex — * for glob matching (at*, *at, *at*) versus grep’s regular expressions (., .*, .+) — related but different syntaxes worth not confusing.
• Variables, PATH, and permissions — shell vs. environment variables (export), how PATH tells the shell where to find commands, and reading/setting file permissions with chmod.
• Archiving — gzip/gunzip compress a single file; tar packs multiple files and directories into one archive.

Basic commands cheat sheet

Command	What it does
cat file1 file2	Print the contents of one or more files
ls -l	List a directory’s contents (long format)
cp file1 file2	Copy a file
mv file1 file2	Move or rename a file
touch file	Create a file, or update its modified timestamp
rm file	Delete a file
cd dir	Change the current working directory (~ is home)
mkdir dir / rmdir dir	Create / remove a directory (rm -r dir for a non-empty one)
grep root /etc/passwd	Print lines matching a pattern (-i case-insensitive, -v invert)
less file	Page through a large file or long output
pwd	Print the current working directory
diff file1 file2	Show the differences between two text files
find dir -name file -print	Search a directory tree for a file by name
head / tail	Show the first / last lines of a file or stream
sort	Put the lines of a text file in alphanumeric order

Variables, PATH, and permissions

Shell variables hold values inside the current shell session:

HOST=127.0.0.1
echo $HOST

Environment variables are shell variables passed down to every program the shell runs — promote one with export:

STUFF=blah
export STUFF

PATH is the environment variable that lists the directories the shell searches for commands:

echo $PATH
# /usr/local/bin:/usr/bin:/bin

File permissions (r/w/x for read/write/execute) are set with chmod:

chmod 644 file   # rw for you, read-only for everyone else — typical for files
chmod 755 dir    # rwx for you, read/execute for everyone else — typical for dirs and programs

Next steps

• Continue with Just Enough GitHub to put version control on top of your new command-line skills.
• The full companion notes for this video live in the Surfalytics analytics-course repo if you want the complete reference, including the Windows/WSL setup steps and the special characters table.