Essential Terminal Commands¶

A reference of the commands you'll use most often as a data engineer. Bookmark this page.

File & Directory Operations¶

Command	What it does	Example
`mkdir`	Create a directory	`mkdir my-project`
`mkdir -p`	Create nested directories	`mkdir -p src/data/raw`
`touch`	Create an empty file	`touch script.py`
`cp`	Copy a file	`cp data.csv backup.csv`
`cp -r`	Copy a directory	`cp -r src/ src-backup/`
`mv`	Move or rename	`mv old.txt new.txt`
`rm`	Delete a file	`rm unwanted.txt`
`rm -r`	Delete a directory	`rm -r old-project/`

Be careful with rm

There is no trash can in the terminal. rm deletes permanently. Always double-check before running rm -r on a directory.

Viewing File Contents¶

# Print the entire file
cat data.csv

# View with scrolling (press q to quit)
less data.csv

# See the first 10 lines
head data.csv

# See the first 20 lines
head -n 20 data.csv

# See the last 10 lines
tail data.csv

# Watch a file update in real time (great for logs)
tail -f app.log

Searching & Filtering¶

# Find text in a file
grep "CO2" data.csv

# Find text, case-insensitive
grep -i "carbon" README.md

# Find files by name
find . -name "*.py"

# Count lines in a file
wc -l data.csv

Pipes and Redirection¶

Pipes (|) connect the output of one command to the input of another. This is one of the most powerful ideas in the terminal.

# Count how many Python files you have
find . -name "*.py" | wc -l

# Find lines with "error" in a log, show just the first 5
grep "error" app.log | head -n 5

# Sort a CSV and save to a new file
sort data.csv > sorted_data.csv

# Append output to a file (instead of overwriting)
echo "new line" >> notes.txt

Environment & System¶

# See environment variables
env

# Print a specific variable
echo $HOME
echo $PATH

# See running processes
ps aux

# Check disk space
df -h

# Check folder size
du -sh my-project/

Python-Specific Commands¶

Since we'll be using Python with Conda in the demo project:

# Check Python version
python --version

# Create a conda environment
conda create -n myproject python=3.12 -y

# Activate it
conda activate myproject

# Install packages
conda install pandas matplotlib -y

# Or use pip inside the conda environment
pip install some-package

# Run a script
python my_script.py

# Deactivate the conda environment
conda deactivate

Keyboard Shortcuts¶

These work in most terminals and will save you a lot of time:

Shortcut	Action
`Tab`	Auto-complete file/folder names
`Ctrl + C`	Cancel the current command
`Ctrl + L`	Clear the screen
`Ctrl + A`	Jump to the beginning of the line
`Ctrl + E`	Jump to the end of the line
`Up Arrow`	Previous command
`Ctrl + R`	Search command history

Quick Reference Card¶

Cheat sheet — click to expand

NAVIGATE           FILES              VIEW
pwd                mkdir dir          cat file
ls / ls -la        touch file         less file
cd dir             cp src dst         head file
cd ..              mv src dst         tail file
cd ~               rm file            grep pat file

PIPES              CONDA/PYTHON       SHORTCUTS
cmd1 | cmd2        conda create -n x  Tab    = autocomplete
cmd > file         conda activate x   Ctrl+C = cancel
cmd >> file        conda install pkg  Ctrl+L = clear
cmd 2>&1           python script.py   Ctrl+R = search history

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