bash-linux

# Bash Linux Patterns > Essential patterns for Bash on Linux/macOS. --- ## 1. Operator Syntax ### Chaining Commands | Operator | Meaning | Example | |----------|---------|---------| | `;` | Run sequentially | `cmd1; cmd2` | | `&&` | Run if previous succeeded | `npm install && npm run dev` | | `\|\|` | Run if previous failed | `npm test \|\| echo "Tests failed"` | | `\|` | Pipe output | `ls \| grep ".js"` | --- ## 2. File Operations ### Essential Commands | Task | Command | |------|---------| | List all | `ls -la` | | Find files | `find . -name "*.js" -type f` | | File content | `cat file.txt` | | First N lines | `head -n 20 file.txt` | | Last N lines | `tail -n 20 file.txt` | | Follow log | `tail -f log.txt` | | Search in files | `grep -r "pattern" --include="*.js"` | | File size | `du -sh *` | | Disk usage | `df -h` | --- ## 3. Process Management | Task | Command | |------|---------| | List processes | `ps aux` | | Find by name | `ps aux \| grep node` | | Kill by PID | `kill -9 <PID>` | | Find port user | `lsof -i :3000` | | Kill port | `kill -9 $(lsof -t -i :3000)` | | Background | `npm run dev &` | | Jobs | `jobs -l` | | Bring to front | `fg %1` | --- ## 4. Text Processing ### Core Tools | Tool | Purpose | Example | |------|---------|---------| | `grep` | Search | `grep -rn "TODO" src/` | | `sed` | Replace | `sed -i 's/old/new/g' file.txt` | | `awk` | Extract columns | `awk '{print $1}' file.txt` | | `cut` | Cut fields | `cut -d',' -f1 data.csv` | | `sort` ...