Linux/Mac Command Line Cheat Sheet

Access this command line cheat sheet for quick reference to essential Linux and Mac terminal commands. It covers file management, navigation, viewing and editing files, searching text, scripting basics, networking commands, and practical command examples.

For QA engineers and automation students, terminal confidence matters. You will use the command line to run tests, inspect logs, manage files, work with Git, start Docker containers, connect to servers, and debug automation projects.

Table Of Contents

• Command Line Cheat Sheet
• Navigating The File System
• File And Directory Management
• Viewing And Editing Files
• Searching And Filtering Text
• Scripting Basics
• Command Line For Networking
• Command Line Tools And Utilities
• Commands And Examples
• Tail Command Tutorial
• Grep Command Tutorial

Command Line Cheat Sheet

Navigating The File System

pwd
ls -l
ls -la
cd /home/user
cd ..
touch newfile.txt
clear

File And Directory Management

mkdir new_folder
mkdir -p new_folder/nested_folder
rm file.txt
rm -r folder
mv old_name.txt new_name.txt
mv file.txt /new/location/
cp file.txt copy_of_file.txt
cp -r dir1 dir2

Viewing And Editing Files

cat file.txt
cat file1.txt file2.txt
nano file.txt
less file.txt
head file.txt
head -n 20 file.txt
tail file.txt
tail -n 20 file.txt
tail -f file.txt

Searching And Filtering Text

grep "search_term" file.txt
grep -i "search_term" file.txt
grep -r "search_term" /path/to/directory
grep -ri "search_term" /path/to/directory
grep -rl "search_term" /path/to/directory
find /path -name "filename"
find . -type f -name "*.txt"
awk '{print $1}' file.txt
sed 's/old/new/g' file.txt

Scripting Basics

bash script.sh
bash -x script.sh
sh script.sh
sh -v script.sh

Command Line For Networking

ping google.com
ping -c 4 google.com
ssh user@hostname
ssh -i ~/.ssh/id_rsa user@hostname

Command Line Tools And Utilities

tar -cvf archive.tar file1 file2
tar -xvf archive.tar

Commands And Examples

The cheat sheet above gives quick command references. The examples below explain how to use important commands in real workflows.

Tail Command Tutorial

The tail command displays the last part of a file. It is especially useful for monitoring log files that are constantly being updated.

Basic Usage: View The Last 10 Lines

tail filename

This displays the last 10 lines of filename. It is useful when you want to quickly check the newest content in a log file or configuration file without opening the whole file.

Customize Line Count

tail -n 100 filename

The -n flag lets you specify exactly how many lines you want to see from the end of the file. For example, tail -n 100 filename shows the last 100 lines.

This is useful when you need more context than the default 10 lines but do not want to read the whole file.

Follow A File In Real Time

tail -n 100 -f filename

The -f flag puts tail into follow mode. Instead of showing the current end of the file and exiting, it keeps watching the file and displays new lines as they are added.

This is one of the most useful commands for QA and debugging. For example, if a web application is writing to app.log, you can run:

tail -n 100 -f app.log

You will see the last 100 log entries first, then new log entries will appear live as the app runs.

Use this when:

• Monitoring test logs
• Watching server logs
• Debugging application behavior
• Confirming whether an action triggers expected backend events

Stop following the file with Ctrl+C.

Grep Command Tutorial

The grep command searches for text patterns inside files and command output. It is one of the most useful tools for debugging, log analysis, and searching through code.

Search In A Single File

grep "search_term" file.txt

This searches for the exact text search_term inside file.txt and prints matching lines. The search is case-sensitive by default, so Error and error are different matches.

Example:

grep "ERROR" app.log

This shows every line in app.log that contains ERROR.

Case-Insensitive Search

grep -i "search_term" file.txt

The -i flag ignores letter case. This means it matches error, Error, ERROR, and other case variations.

Example:

grep -i "error" app.log

Use this when logs or files are inconsistent about capitalization.

Recursive Directory Search

grep -r "search_term" /path/to/directory

The -r flag searches recursively through all files in the directory and its subdirectories.

Example:

grep -r "function_name" /path/to/project

This is useful when searching through a codebase for a function, setting, test name, endpoint, or error message.

Recursive Case-Insensitive Search

grep -ri "search_term" /path/to/directory

You can combine flags. The -ri combination searches recursively and ignores case.

Example:

grep -ri "database" /path/to/project

This finds database, Database, DATABASE, and other case variations across the project.

Show Only File Names With Matches

grep -rl "search_term" /path/to/directory

The -l flag shows only file names that contain matches instead of printing every matching line.

Example:

grep -rl "TODO" /path/to/project

This lists every file that contains TODO.

Filter Command Output With Grep

You can combine grep with other commands using pipes:

ls -la | grep ".txt"

This filters the directory listing and only shows lines containing .txt.

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