Building a Linux Command Reference Sheet

Everyone tells you to learn Linux before DevOps, but no one tells you what specific parts of Linux to focus on. 👉 Linux topics to learn before other DevOps tools: 🔺 Process Management: Check running processes, their CPU and memory utilization using commands like ps, top, htop, and kill. View process hierarchy with pstree to understand parent-child relationships 🔺Networking: Master commands to check network interfaces (ifconfig, ip), firewall configuration (iptables, ufw), used ports (netstat, ss), and general connectivity (ping, traceroute, dig) 🔺File Structure Manipulation: Get comfortable with file/directory creation, copying/moving data, navigating directory trees, and understanding absolute vs. relative paths (mkdir, cp, mv, cd, pwd) 🔺File Permissions & Ownership: Learn to manage who can read, write, or execute files using chmod, chown, and chgrp. Understand numeric and symbolic permission notation (755, u+x) 🔺File System Usage: Learn commands like df (disk free space), du (disk usage), and related tools to monitor storage 🔺Search & Filter: Practice finding files with various parameters (find), searching patterns in files (grep, sed), and filtering data outputs (cut, awk, sort) 🔺Package Management: Understand how to install/uninstall packages using package managers like apt, yum, or dnf 🔺System Configuration: Learn about system information commands, startup scripts, profile files (.bashrc, .profile), and how to create useful aliases 🔺System Monitoring: Master commands to check system load (uptime), CPU and memory usage (free, vmstat, sar), and swap utilization (swapon --show) 🔺Service Management: Get familiar with both systemctl commands (systemctl start/stop/restart/status) and legacy service commands for managing system services 🔺SSH Configuration: Learn to set up secure remote connections, configure SSH keys, and customize settings in /etc/ssh/sshd_config 🔺Basic Shell Scripting: Learn how to automate routine tasks with bash scripts, including variables, loops, conditionals, and functions 🔺System Information: Use commands like uname to get kernel information, architecture details, and other system specifics Remember, you'll always pick up additional Linux skills while working in DevOps.

I just created a handy Linux Essential Commands Cheatsheet for daily use! Having these fundamental Linux commands at your fingertips can be a real-time-saver. I've compiled the most frequently used commands into an easy-to-reference guide. Key categories include: • File operations (ls, cd, pwd) • System monitoring (top, ps) • File permissions (chmod, chown) • Text operations (grep, cat) • Network commands (ping, ssh, wget) What do you think? Did I miss any essential commands that you use daily? I'd love to hear your must-have Linux commands! Some commands I'm considering adding: • df -h (check disk space) • htop (interactive process viewer) • tail -f (monitor log files) • find (search for files) • tar (archive management)

Most Used Linux Commands in My 15+ Years as a Developer  Here’s a quick and handy cheat sheet I’ve relied on from junior roles to technical lead positions:  ⮑ System Information   - uname -a – Show system information.   - uptime – Display system uptime.   - hostname – Show hostname.   - whoami – Display current logged-in user.   - top – Show running processes in real time.  ⮑ File Management   - ls -al – List all files and directories with details.   - pwd – Show current directory path.   - cd [dir] – Change directory.   - cp [source] [dest] – Copy files.   - mv [source] [dest] – Move or rename files.   - rm [file] – Remove a file.   - find [dir] -name [file] – Search for files.   - grep [pattern] [file] – Search text in files.  ⮑ Permissions   - chmod 755 [file] – Change permissions.   - chown user:group [file] – Change file ownership.   - ls -l – View file permissions.  ⮑ Process Management   - ps aux – Show running processes.   - top – Monitor processes in real time.   - kill [PID] – Kill a process by PID.   - pkill [name] – Kill processes by name.   - jobs – List background jobs.   - fg [job_id] – Bring a background job to foreground.  --- ⮑ Networking   - ping [host] – Test network connectivity.   - curl -I [URL] – Get HTTP headers.   - wget [URL] – Download files.   - ifconfig – Show network interfaces.   - netstat -tuln – View open ports.   - dig [domain] – Get DNS information.  ⮑ Compression and Archives   - tar -cvf [file.tar] [dir] – Archive files.   - tar -xvf [file.tar] – Extract files.   - gzip [file] – Compress files.   - gunzip [file.gz] – Decompress files.  ⮑ Disk Usage   - df -h – Show disk usage in human-readable form.   - du -sh [dir] – Show size of directory.   - lsblk – List information about block devices.   - mount – List mounted filesystems.  ⮑ Package Management   - apt update – Update package lists (Debian/Ubuntu).   - apt install [package] – Install a package.   - yum install [package] – Install a package (RHEL/CentOS).   - rpm -q [package] – Check if a package is installed.  ⮑ Logs and Monitoring   - dmesg – View system logs.   - tail -f [file] – View live logs.   - journalctl -xe – View detailed logs for errors.  

A Cheat Sheet on The Most-Used Linux Commands Linux has thousands of commands. Most engineers use about 20 or so commands every day, not because Linux is limited, but because that core set handles the bulk of actual work: navigating files, inspecting logs, debugging processes, checking system health, and fixing things under pressure. This cheat sheet maps out the most-used Linux commands by category: - File management basics like ls, cd, cp, mv, and rm that you touch constantly without thinking. - File viewing and editing with cat, less, head, tail, nano, and vim when logs are huge and time is short. - Text processing with grep, awk, sort, and diff to turn raw logs into answers. - Permissions with chmod and chown, because something always breaks due to access issues. - Networking commands like ssh, scp, curl, ping, ss, and ip for debugging remote systems. - Process and system inspection using ps, top, htop, df, free, and uname to see what the machine is really doing. - Archiving, package management, system control, and help commands that glue everything together. Over to you: Which Linux command do you end up using the most during real incidents? -- Subscribe to our weekly newsletter to get a Free System Design PDF (158 pages): https://lnkd.in/g9wAgcke #systemdesign #coding #interviewtips  .