UNIX/Linux Cheatsheet
Essential commands for daily terminal work. Your go-to reference!
📁 File & Directory Navigation
pwd # Print current working directory
ls # List files in current directory
ls -la # List all files with details (including hidden)
ls -lh # List with human-readable file sizes
ls -lt # List sorted by modification time
cd <directory> # Change directory
cd ~ # Go to home directory
cd - # Go to previous directory
cd .. # Go up one directory
tree # Display directory tree structure
tree -L 2 # Tree with depth limit of 2
📄 File Operations
touch <file> # Create empty file or update timestamp
cp <src> <dest> # Copy file
cp -r <src> <dest> # Copy directory recursively
mv <src> <dest> # Move or rename file/directory
rm <file> # Remove file
rm -rf <directory> # Remove directory and contents (careful!)
mkdir <dir> # Create directory
mkdir -p <path/to/dir> # Create nested directories
rmdir <dir> # Remove empty directory
ln -s <target> <link> # Create symbolic link
file <filename> # Determine file type
stat <file> # Display file status and metadata
👀 Viewing File Contents
cat <file> # Display entire file content
less <file> # View file with pagination (q to quit)
more <file> # View file page by page
head <file> # Show first 10 lines
head -n 20 <file> # Show first 20 lines
tail <file> # Show last 10 lines
tail -n 50 <file> # Show last 50 lines
tail -f <file> # Follow file in real-time (great for logs)
wc <file> # Count lines, words, characters
wc -l <file> # Count lines only
🔍 Search & Find
find . -name "*.txt" # Find files by name pattern
find . -type f -mtime -7 # Files modified in last 7 days
find . -type d -name "logs" # Find directories by name
find . -size +100M # Find files larger than 100MB
find . -empty # Find empty files and directories
locate <filename> # Quick find using database (run updatedb first)
which <command> # Show path of command
whereis <command> # Locate binary, source, and man page
type <command> # Show how command would be interpreted
🔎 Text Search (grep)
grep "pattern" <file> # Search for pattern in file
grep -i "pattern" <file> # Case-insensitive search
grep -r "pattern" <directory> # Recursive search in directory
grep -n "pattern" <file> # Show line numbers
grep -v "pattern" <file> # Invert match (lines NOT matching)
grep -c "pattern" <file> # Count matching lines
grep -l "pattern" * # List files containing pattern
grep -E "regex" <file> # Extended regex (egrep)
grep -A 3 "pattern" <file> # Show 3 lines after match
grep -B 3 "pattern" <file> # Show 3 lines before match
✂️ Text Processing
cut -d',' -f1 <file> # Extract first field (comma delimiter)
cut -c1-10 <file> # Extract characters 1-10
sort <file> # Sort lines alphabetically
sort -n <file> # Sort numerically
sort -r <file> # Sort in reverse
sort -u <file> # Sort and remove duplicates
uniq <file> # Remove adjacent duplicates
uniq -c <file> # Count occurrences
tr 'a-z' 'A-Z' < file # Translate lowercase to uppercase
tr -d '\n' < file # Delete newlines
sed 's/old/new/g' <file> # Replace text (global)
sed -i 's/old/new/g' <file> # Replace in-place
sed -n '5,10p' <file> # Print lines 5-10
awk '{print $1}' <file> # Print first column
awk -F',' '{print $2}' <file> # Print second column (comma delim)
awk '{sum+=$1} END {print sum}' <file> # Sum first column
📝 File Permissions
chmod 755 <file> # rwxr-xr-x (owner full, others read/exec)
chmod 644 <file> # rw-r--r-- (owner rw, others read)
chmod +x <file> # Add execute permission
chmod -w <file> # Remove write permission
chmod u+x <file> # Add execute for user only
chmod -R 755 <dir> # Recursive permission change
chown <user> <file> # Change file owner
chown <user>:<group> <file> # Change owner and group
chown -R <user> <dir> # Recursive ownership change
chgrp <group> <file> # Change group ownership
💽 Disk & Storage
df -h # Disk space usage (human readable)
df -i # Inode usage
du -sh <dir> # Directory size summary
du -h --max-depth=1 # Size of subdirectories
du -ah | sort -rh | head -20 # Top 20 largest files/dirs
lsblk # List block devices
mount # Show mounted filesystems
fdisk -l # List disk partitions
⚙️ Process Management
ps # List your processes
ps aux # List all processes
ps aux | grep <name> # Find specific process
top # Interactive process viewer
htop # Better interactive viewer (if installed)
kill <pid> # Terminate process by PID
kill -9 <pid> # Force kill process
killall <name> # Kill all processes by name
pkill <pattern> # Kill processes matching pattern
pgrep <pattern> # Find PIDs by pattern
jobs # List background jobs
bg # Resume job in background
fg # Bring job to foreground
nohup <command> & # Run command immune to hangups
🌐 Networking
ping <host> # Test network connectivity
curl <url> # Transfer data from URL
curl -O <url> # Download file
wget <url> # Download file
wget -c <url> # Resume download
ifconfig # Show network interfaces (deprecated)
ip addr # Show IP addresses (modern)
ip route # Show routing table
netstat -tuln # List listening ports
ss -tuln # Modern alternative to netstat
lsof -i :8080 # What's using port 8080
nc -zv <host> <port> # Test if port is open
dig <domain> # DNS lookup
nslookup <domain> # DNS lookup (interactive)
host <domain> # Simple DNS lookup
traceroute <host> # Trace packet route
ssh <user>@<host> # SSH into remote host
scp <file> <user>@<host>:<path> # Secure copy to remote
rsync -avz <src> <dest> # Sync files/directories
📦 Compression & Archives
tar -cvf archive.tar <files> # Create tar archive
tar -xvf archive.tar # Extract tar archive
tar -czvf archive.tar.gz <files> # Create gzipped tar
tar -xzvf archive.tar.gz # Extract gzipped tar
tar -cjvf archive.tar.bz2 <files> # Create bzip2 tar
tar -xjvf archive.tar.bz2 # Extract bzip2 tar
tar -tvf archive.tar # List contents without extracting
gzip <file> # Compress file (.gz)
gunzip <file.gz> # Decompress .gz file
zip archive.zip <files> # Create zip archive
unzip archive.zip # Extract zip archive
unzip -l archive.zip # List zip contents
📊 System Information
uname -a # All system info
hostname # Show hostname
uptime # System uptime and load
whoami # Current username
id # User ID and group info
w # Who is logged in and what they're doing
last # Recent login history
free -h # Memory usage (human readable)
cat /etc/os-release # OS information
lscpu # CPU information
lsmem # Memory information
dmesg # Kernel ring buffer messages
🔧 Environment & Variables
env # Show all environment variables
echo $PATH # Print PATH variable
export VAR=value # Set environment variable
export PATH=$PATH:/new/path # Add to PATH
unset VAR # Remove environment variable
printenv VAR # Print specific variable
source ~/.bashrc # Reload bash config
alias ll='ls -la' # Create alias
alias # List all aliases
history # Show command history
history | grep <cmd> # Search history
!<number> # Run command from history
!! # Repeat last command
📡 Pipes & Redirection
command > file # Redirect stdout to file (overwrite)
command >> file # Redirect stdout to file (append)
command 2> file # Redirect stderr to file
command &> file # Redirect both stdout and stderr
command < file # Use file as stdin
command1 | command2 # Pipe output to another command
command | tee file # Pipe and also save to file
command1 && command2 # Run command2 if command1 succeeds
command1 || command2 # Run command2 if command1 fails
command1 ; command2 # Run both regardless of result
🛠️ Useful One-Liners
# Find and delete files older than 30 days
find . -type f -mtime +30 -delete
# Count files in directory
find . -type f | wc -l
# Find largest files in directory
find . -type f -exec du -h {} + | sort -rh | head -10
# Replace text in multiple files
find . -name "*.txt" -exec sed -i 's/old/new/g' {} +
# Monitor log file in real-time with highlighting
tail -f /var/log/syslog | grep --color=auto "error"
# Get your public IP
curl -s ifconfig.me
# Quick HTTP server (Python 3)
python3 -m http.server 8000
# Generate random password
openssl rand -base64 16
# Check if port is in use
lsof -i :<port> || echo "Port is free"
# Recursively find duplicate files by checksum
find . -type f -exec md5sum {} + | sort | uniq -d -w32
📚 Useful Links
| Resource | Link |
|---|---|
| GNU Coreutils Manual | gnu.org/software/coreutils/manual |
| Linux Man Pages | man7.org |
| ExplainShell | explainshell.com |
| TLDR Pages | tldr.sh |
| Linux Command Library | linuxcommandlibrary.com |
| SS64 Command Reference | ss64.com/bash |
| Bash Reference Manual | gnu.org/software/bash/manual |
| ShellCheck | shellcheck.net |
Pro Tips
- Use
man <command>to read the manual for any command - Press
Tabfor auto-completion - Use
Ctrl+Rto search command history - Use
Ctrl+Cto cancel,Ctrl+Zto suspend - Wrap variables in quotes:
"$VAR"to handle spaces - Use
--helpflag for quick command help
Last updated: February 2026