Linux Commands Every Developer Must Know: The 50 Commands You Use Daily

Linux command-line proficiency is the multiplier that makes every other developer skill faster. Debugging in production, scripting deployments, searching logs, managing processes, and setting up servers — all of it goes 10x faster when you know the right commands. These 50 are the ones senior engineers reach for every single day.

⚡ TL;DR: Master grep with -r, -l, -n, -E. Know awk for column extraction. Know sed for in-place replacement. Know find with -exec. Know ps, kill, lsof, netstat. Know ssh port forwarding. Know chmod, chown. Know tail -f and journalctl -f for live logs.

File search and manipulation

# grep — search file contents
grep -r "TODO" ./src              # Recursive search
grep -rn "console.log" ./src     # With line numbers
grep -rl "TODO" ./src            # Only filenames (not content)
grep -E "error|warning" app.log  # Extended regex (OR)
grep -v "DEBUG" app.log          # Invert: exclude DEBUG lines
grep -A 3 -B 3 "ERROR" app.log  # 3 lines after AND before match

# find — find files by any criteria
find . -name "*.ts" -type f                    # All TypeScript files
find . -mtime -1 -type f                       # Modified in last 24h
find . -size +10M -type f                      # Files over 10MB
find . -name "*.log" -exec rm {} \;            # Delete all log files
find . -name "*.js" -exec grep -l "require" {} \; # JS files using require

# sed — stream editor for text transformation
sed 's/old/new/g' file.txt                    # Replace all occurrences
sed -i 's/old/new/g' file.txt                 # In-place replacement
sed -n '5,10p' file.txt                       # Print lines 5-10
sed '/^#/d' config.txt                         # Delete comment lines

Process management

# Process inspection
ps aux | grep node                    # Find Node.js processes
ps aux --sort=-%cpu | head -10        # Top 10 CPU-consuming processes
ps aux --sort=-%mem | head -10        # Top 10 memory consumers

# Kill processes
kill -9 PID                           # Force kill by PID
pkill -f "node server.js"            # Kill by command name pattern
killall node                          # Kill all node processes

# Background jobs
nohup ./start.sh &                    # Run in background, survives logout
command &                             # Background job
jobs                                  # List background jobs
fg 1                                  # Bring job 1 to foreground
bg 1                                  # Send job 1 to background

# Resource monitoring
top                                   # Interactive process monitor
htop                                  # Better top (if installed)
vmstat 1                              # Memory/CPU stats every second
iostat 1                              # Disk I/O stats
free -h                               # Memory usage human-readable

Networking essentials

# Port and connection inspection
netstat -tlnp                         # All listening ports with PID
ss -tlnp                              # Modern alternative to netstat
lsof -i :3000                         # What's using port 3000
lsof -p PID                           # All files opened by process
curl -I https://example.com           # HTTP headers only
curl -o /dev/null -w "%{http_code}" https://example.com  # Just status code

# SSH power user
ssh -L 5432:db-server:5432 user@bastion    # Port forward: local 5432 → remote DB
ssh -R 8080:localhost:3000 user@server     # Expose local port on remote
ssh -N -f user@server -L 5432:localhost:5432  # Background tunnel

# Network debugging
ping -c 4 google.com               # 4 ICMP pings
traceroute google.com              # Show network hops
curl -v https://example.com        # Verbose: see headers, TLS, timing
wget -O output.html https://example.com  # Download to file

Log analysis

# Real-time log watching
tail -f /var/log/app.log              # Follow live updates
tail -f /var/log/app.log | grep ERROR # Follow + filter
journalctl -fu myservice              # systemd service logs, follow

# Log analysis one-liners
# Count error occurrences by type:
grep "ERROR" app.log | awk '{print $5}' | sort | uniq -c | sort -rn

# Top 10 IP addresses from nginx access log:
awk '{print $1}' /var/log/nginx/access.log | sort | uniq -c | sort -rn | head -10

# Response time distribution from nginx:
awk '{print $NF}' /var/log/nginx/access.log | sort -n | awk '
BEGIN{a[""]=0} {a[int($1*10)/10]++} END{for(i in a)print i, a[i]}' | sort -n

# Find slow requests (>1s):
awk '$NF > 1.0 {print $0}' /var/log/nginx/access.log

Essential one-liners

• du -sh * | sort -rh | head -10 — largest files/dirs in current directory
• df -h — disk space usage human-readable
• history | grep "git push" — search command history
• !! — repeat last command; sudo !! — repeat with sudo
• ctrl+r — reverse search through command history
• wc -l file.txt — count lines in file
• cat file.txt | sort | uniq -c | sort -rn — frequency count
• tar -czf archive.tar.gz dir/ — compress; tar -xzf archive.tar.gz — extract
• chmod 755 script.sh — rwxr-xr-x (owner all, others read+execute)
• crontab -e — edit cron jobs; 0 2 * * * /path/script.sh — run at 2AM daily

Linux command proficiency is foundational for the Docker best practices guide — Dockerfiles are essentially Linux command scripts. For production debugging, the PostgreSQL production debugging guide combines these Linux skills with database-specific tools. External reference: TLDR Pages — simplified man pages.