Linux

Bookmark this page. Use Ctrl+F (or Cmd+F on Mac) to find what you need. This cheat sheet covers essential terminal commands for macOS and Linux. Last updated: March 2026 Navigation Command Description pwd Print current directory ls List files ls -la List all files with details (including hidden) ls -lh List with human-readable sizes cd /path Change directory cd ~ Go to home directory cd .. Go up one directory cd - Go to previous directory tree Show directory tree (install: brew install tree) tree -L 2 Tree with max depth 2 Files and Directories Command Description touch file.txt Create empty file mkdir mydir Create directory mkdir -p a/b/c Create nested directories cp file.txt copy.txt Copy file cp -r dir/ newdir/ Copy directory recursively mv file.txt newname.txt Rename/move file rm file.txt Delete file rm -r dir/ Delete directory recursively rm -rf dir/ Force delete (no confirmation) ln -s target link Create symbolic link cat file.txt Print file contents head -20 file.txt First 20 lines tail -20 file.txt Last 20 lines tail -f file.log Follow file in real-time (logs) less file.txt Paginated viewer (q to quit) wc -l file.txt Count lines wc -w file.txt Count words diff file1 file2 Compare two files stat file.txt File details (size, dates, permissions) Searching Command Description grep "text" file.txt Search for text in file grep -r "text" dir/ Search recursively in directory grep -i "text" file.txt Case-insensitive search grep -n "text" file.txt Show line numbers grep -c "text" file.txt Count matches grep -v "text" file.txt Show lines NOT matching find . -name "*.txt" Find files by name find . -type d -name "src" Find directories by name find . -size +10M Find files larger than 10MB find . -mtime -7 Files modified in last 7 days which python Find where a command lives locate file.txt Fast file search (uses index) Pipes and Redirection # Pipe — send output of one command to another ls -la | grep ".txt" cat file.txt | sort | uniq ps aux | grep node # Redirect output to file echo "hello" > file.txt # overwrite echo "world" >> file.txt # append # Redirect errors command 2> errors.log # stderr to file command > output.log 2>&1 # stdout + stderr to file command &> all.log # same (bash shorthand) # /dev/null — discard output command > /dev/null 2>&1 # silence everything cmd1 | cmd2 pipe: stdout of cmd1 → stdin of cmd2 cmd > file redirect stdout to file (overwrite) cmd >> file redirect stdout to file (append) cmd 2> file redirect stderr to file cmd < file use file as stdin Permissions -rwxr-xr-- 1 alex staff 4096 Mar 15 file.txt │├─┤├─┤├─┤ │ │ │ │ │ │ │ └── Others: read only │ │ └───── Group: read + execute │ └───────── Owner: read + write + execute └─────────── File type (- = file, d = directory, l = link) Command Description chmod 755 file rwxr-xr-x (owner all, group/others read+exec) chmod 644 file rw-r–r– (owner read+write, others read) chmod +x script.sh Add execute permission chmod -w file.txt Remove write permission chown user:group file Change owner and group chown -R user dir/ Change owner recursively Number Permission 7 rwx (read + write + execute) 6 rw- (read + write) 5 r-x (read + execute) 4 r– (read only) 0 — (no permission) Processes Command Description ps aux List all processes ps aux | grep node Find a specific process top Live process monitor htop Better process monitor (install separately) kill <pid> Send SIGTERM (graceful stop) kill -9 <pid> Send SIGKILL (force stop) killall node Kill all processes by name lsof -i :3000 Find what is using port 3000 jobs List background jobs bg Resume job in background fg Bring job to foreground command & Run command in background nohup command & Run and keep running after logout Disk and System Command Description df -h Disk usage (human-readable) du -sh dir/ Directory size du -sh * | sort -rh Largest items in current dir free -h Memory usage (Linux) uname -a System info hostname Machine name uptime System uptime and load date Current date/time cal Calendar Networking Command Description curl https://example.com Fetch a URL curl -o file.html https://example.com Download to file curl -X POST -d '{"key":"value"}' -H "Content-Type: application/json" url POST JSON wget https://example.com/file.zip Download a file ping example.com Test connectivity ifconfig / ip addr Show network interfaces netstat -tlnp / ss -tlnp Show listening ports ssh user@host Connect via SSH scp file.txt user@host:/path Copy file to remote scp user@host:/path/file.txt . Copy file from remote Archives Command Description tar -czf archive.tar.gz dir/ Create gzip archive tar -xzf archive.tar.gz Extract gzip archive tar -xzf archive.tar.gz -C /dest Extract to directory zip -r archive.zip dir/ Create zip archive unzip archive.zip Extract zip Text Processing # Sort lines sort file.txt sort -r file.txt # reverse sort -n file.txt # numeric sort sort -u file.txt # unique only # Unique lines (file must be sorted first) sort file.txt | uniq sort file.txt | uniq -c # count occurrences # Cut columns cut -d',' -f1,3 data.csv # columns 1 and 3 (comma delimiter) # Replace text sed 's/old/new/g' file.txt # replace all occurrences sed -i 's/old/new/g' file.txt # in-place edit (Linux) sed -i '' 's/old/new/g' file.txt # in-place edit (macOS — needs empty '') # Print specific lines awk '{print $1, $3}' file.txt # columns 1 and 3 (space delimiter) awk -F',' '{print $1}' data.csv # with custom delimiter # Count and summarize cat access.log | awk '{print $1}' | sort | uniq -c | sort -rn | head -10 # → top 10 IP addresses in an access log Keyboard Shortcuts (Terminal) Shortcut Action Ctrl+C Cancel current command Ctrl+D Exit shell / close terminal Ctrl+Z Suspend current process Ctrl+L Clear screen Ctrl+R Search command history Ctrl+A Move cursor to start of line Ctrl+E Move cursor to end of line Ctrl+W Delete word before cursor Ctrl+U Delete entire line before cursor Tab Auto-complete file/command name !! Repeat last command !$ Last argument of previous command Environment Variables echo $HOME # print variable export MY_VAR="value" # set for current session echo 'export MY_VAR="value"' >> ~/.zshrc # permanent (Zsh) echo 'export MY_VAR="value"' >> ~/.bashrc # permanent (Bash) env # list all env variables printenv PATH # print specific variable Common Mistakes rm -rf / or rm -rf * — There is no recycle bin in the terminal. Deleted files are gone. Always double-check your path before running rm -rf. Use ls first to preview what will be deleted. ...