🧭 Navigation
pwd # where am I ls -lah # all + size cd /var/www/html cd ~ # home cd - # previous tree -L 2 # 2-level tree
📄 File Operations
touch file.txt mkdir -p /app/logs cat file.txt less file.txt # paged head -20 file.txt tail -20 file.txt tail -f /var/log/nginx/error.log # live 🔥 cp source dest cp -r src/ dest/ mv old new rm file rm -rf folder/ # ⚠️ irreversible
🔍 Find & Grep
find / -name "nginx.conf" find /var/www -name "*.php" find /tmp -mtime +7 -delete find . -size +100M grep -i "error" log.txt grep -n "TODO" *.php grep -r "API_KEY" /var/www/ grep -v "info" log.txt grep -A 3 -B 2 "ERROR" log.txt tail -f log | grep --line-buffered ERROR # 🔥
💾 Disk Usage
df -h # disk space 🔥 du -sh /var/www/* # folder sizes du -sh * | sort -rh | head -10 ncdu / # interactive
🔢 Pipe & Redirect
cat log | grep 404 | wc -l ps aux | grep nginx echo "x" > file # overwrite echo "y" >> file # append cmd 2> err.log # stderr cmd > out 2>&1 # both cmd &> all.log # bash shortcut
⚡ Shortcuts
Ctrl+R # search history 🔥 Ctrl+L # clear Ctrl+A/E # line start/end !! # last command sudo !! # repeat with sudo history | grep nginx
🎓 মূল কথা ⭐
10 command = 90% কাজ। Ctrl+R history search use করুন। Daily practice ছাড়া fluency আসবে না।