Linux Commands Cheat Sheet: Essential Commands Every Developer Needs

Navigation and File Management

Moving Around

# Print current directory
pwd

# Change directory
cd /path/to/dir
cd ~              # Home directory
cd -              # Previous directory
cd ..             # Parent directory
cd ../..          # Two levels up

# List files
ls                # Basic listing
ls -la            # Long format, show hidden files
ls -lh            # Human-readable file sizes
ls -lt            # Sort by modification time
ls -lS            # Sort by file size
ls -R             # Recursive listing

File Operations

# Create files
touch file.txt                    # Create empty file
echo "hello" > file.txt           # Create with content
echo "more" >> file.txt           # Append to file

# Create directories
mkdir mydir                       # Create directory
mkdir -p path/to/nested/dir       # Create nested directories

# Copy
cp file.txt copy.txt              # Copy file
cp -r dir/ dir_copy/              # Copy directory recursively
cp -i file.txt dest/              # Interactive (confirm overwrite)

# Move / Rename
mv file.txt newname.txt           # Rename
mv file.txt /path/to/dest/        # Move
mv -i file.txt dest/              # Interactive

# Delete
rm file.txt                       # Delete file
rm -r dir/                        # Delete directory recursively
rm -rf dir/                       # Force delete (no confirmation)
rm -i file.txt                    # Interactive (confirm)

# Find files
find . -name "*.js"               # Find by name
find . -name "*.log" -delete      # Find and delete
find . -type f -size +100M        # Files larger than 100MB
find . -type f -mtime -7          # Modified in last 7 days
find . -type f -empty             # Empty files
find /path -name "*.txt" -exec grep -l "pattern" {} \;

Viewing Files

# View entire file
cat file.txt

# View with line numbers
cat -n file.txt

# View first/last lines
head file.txt                     # First 10 lines
head -n 20 file.txt               # First 20 lines
tail file.txt                     # Last 10 lines
tail -n 20 file.txt               # Last 20 lines
tail -f logfile.log               # Follow (live updates)

# Page through a file
less file.txt                     # Scrollable viewer
# In less: q=quit, /=search, n=next match, g=top, G=bottom

# View file with syntax highlighting
bat file.txt                      # If bat is installed

Text Processing

grep — Search Text

# Search for pattern in file
grep "error" logfile.log

# Case-insensitive search
grep -i "error" logfile.log

# Recursive search in directory
grep -r "TODO" src/

# Show line numbers
grep -n "function" app.js

# Count matches
grep -c "error" logfile.log

# Show only filenames with matches
grep -l "import" src/*.ts

# Invert match (lines NOT containing pattern)
grep -v "debug" logfile.log

# Extended regex
grep -E "error|warning|critical" logfile.log

# Context lines (before/after match)
grep -B 2 -A 2 "error" logfile.log

sed — Stream Editor

# Replace first occurrence per line
sed 's/old/new/' file.txt

# Replace all occurrences
sed 's/old/new/g' file.txt

# Replace in-place (modify file)
sed -i 's/old/new/g' file.txt

# Delete lines matching pattern
sed '/pattern/d' file.txt

# Delete empty lines
sed '/^$/d' file.txt

# Print only matching lines
sed -n '/pattern/p' file.txt

# Replace on specific line
sed '3s/old/new/' file.txt

awk — Text Processing

# Print specific columns
awk '{print $1, $3}' file.txt

# Print with custom separator
awk -F',' '{print $1, $2}' data.csv

# Filter rows
awk '$3 > 100' data.txt

# Sum a column
awk '{sum += $1} END {print sum}' numbers.txt

# Count lines
awk 'END {print NR}' file.txt

# Print unique lines
awk '!seen[$0]++' file.txt

Other Text Tools

# Sort lines
sort file.txt                     # Alphabetical
sort -n file.txt                  # Numeric
sort -r file.txt                  # Reverse
sort -u file.txt                  # Unique only
sort -t',' -k2 -n data.csv       # Sort CSV by 2nd column

# Remove duplicate lines
uniq file.txt                     # Remove adjacent duplicates
sort file.txt | uniq              # Remove all duplicates
sort file.txt | uniq -c           # Count occurrences

# Count lines, words, characters
wc file.txt                       # All three
wc -l file.txt                    # Lines only
wc -w file.txt                    # Words only

# Cut columns
cut -d',' -f1,3 data.csv          # Fields 1 and 3
cut -c1-10 file.txt               # Characters 1-10

# Translate characters
tr 'a-z' 'A-Z' < file.txt         # Lowercase to uppercase
tr -d '\n' < file.txt              # Remove newlines
tr -s ' ' < file.txt               # Squeeze spaces

Permissions

# View permissions
ls -la

# Permission format: -rwxrwxrwx
# - = file type (- file, d directory, l symlink)
# rwx = owner permissions (read, write, execute)
# rwx = group permissions
# rwx = other permissions

# Change permissions (symbolic)
chmod u+x script.sh               # Add execute for owner
chmod g+w file.txt                # Add write for group
chmod o-r file.txt                # Remove read for others
chmod a+r file.txt                # Add read for all

# Change permissions (numeric)
chmod 755 script.sh               # rwxr-xr-x
chmod 644 file.txt                # rw-r--r--
chmod 600 secret.key              # rw-------
chmod -R 755 dir/                 # Recursive

# Common permission patterns:
# 755 — Executable scripts, directories
# 644 — Regular files
# 600 — Private files (SSH keys, secrets)
# 700 — Private directories

# Change ownership
chown user:group file.txt
chown -R user:group dir/

Process Management

# View running processes
ps aux                            # All processes
ps aux | grep node                # Filter by name
top                               # Interactive process viewer
htop                              # Better interactive viewer

# Kill processes
kill PID                          # Graceful stop (SIGTERM)
kill -9 PID                       # Force kill (SIGKILL)
killall node                      # Kill all by name
pkill -f "node server"            # Kill by pattern

# Background processes
command &                         # Run in background
jobs                              # List background jobs
fg %1                             # Bring job 1 to foreground
bg %1                             # Resume job 1 in background
nohup command &                   # Run even after logout

# Ctrl+Z = suspend current process
# Ctrl+C = interrupt (kill) current process

Networking

# Download files
curl https://example.com                    # GET request
curl -o file.zip https://example.com/file   # Save to file
curl -X POST -d '{"key":"value"}' -H "Content-Type: application/json" https://api.example.com
wget https://example.com/file.zip           # Download file

# Network info
ifconfig                          # Network interfaces
ip addr                           # Modern alternative
hostname -I                       # Show IP address

# DNS lookup
nslookup example.com
dig example.com

# Test connectivity
ping example.com
ping -c 4 example.com             # 4 pings only

# Check open ports
netstat -tlnp                     # Listening ports
ss -tlnp                          # Modern alternative
lsof -i :3000                     # What's using port 3000

# SSH
ssh user@host                     # Connect
ssh -p 2222 user@host             # Custom port
ssh -i key.pem user@host          # With key file
scp file.txt user@host:/path/     # Copy file to remote
scp user@host:/path/file.txt .    # Copy file from remote

Disk and System

# Disk usage
df -h                             # Filesystem usage
du -sh dir/                       # Directory size
du -sh * | sort -rh | head -10    # Top 10 largest items
ncdu /path                        # Interactive disk usage

# System info
uname -a                          # System information
cat /etc/os-release               # OS version
free -h                           # Memory usage
uptime                            # System uptime
whoami                            # Current user

Compression

# tar (archive)
tar -czf archive.tar.gz dir/      # Create gzipped archive
tar -xzf archive.tar.gz           # Extract gzipped archive
tar -xzf archive.tar.gz -C /dest/ # Extract to specific directory
tar -tf archive.tar.gz            # List contents

# zip
zip -r archive.zip dir/           # Create zip
unzip archive.zip                 # Extract zip
unzip -l archive.zip              # List contents

# gzip
gzip file.txt                     # Compress (replaces original)
gunzip file.txt.gz                # Decompress

Shell Shortcuts

# History
history                           # Show command history
!!                                # Repeat last command
!grep                             # Repeat last grep command
Ctrl+R                            # Search history

# Navigation
Ctrl+A                            # Move to start of line
Ctrl+E                            # Move to end of line
Ctrl+W                            # Delete word before cursor
Ctrl+U                            # Delete to start of line
Ctrl+K                            # Delete to end of line
Ctrl+L                            # Clear screen

# Piping and redirection
command > file.txt                # Redirect stdout to file
command >> file.txt               # Append stdout to file
command 2> error.log              # Redirect stderr
command &> all.log                # Redirect both
command1 | command2               # Pipe stdout to next command
command1 && command2              # Run command2 if command1 succeeds
command1 || command2              # Run command2 if command1 fails