Arch Linux: A Beginner's Command-Line Cheat Sheet

Arch Linux offers unparalleled control but can feel daunting for newcomers. This cheat sheet provides essential commands to confidently manage your system.

1. System Information & Updates

These commands provide vital system details and keep your system secure:

• System Information:

  • uname -a: Displays kernel version, architecture, and more. Example: Linux hostname 6.10.9-arch1-2 #1 SMP PREEMPT_DYNAMIC ... x86_64 GNU/Linux
  • lscpu: Detailed CPU information (cores, architecture, model, speed).
  • free -h: Human-readable memory usage (RAM, swap).

• System Update:

  • sudo pacman -Syu: Synchronizes package databases and upgrades all packages.

• Power Management:

  • sudo poweroff: Shuts down the system.
  • sudo reboot: Reboots the system.
  • logout: Logs out of the current user session.

2. File Management

Essential commands for navigating, creating, and manipulating files and directories:

• Navigation:

  • cd /path/to/directory: Changes the current directory.
  • cd ~: Returns to the home directory.
  • ls: Lists files and directories.
  • ls -l: Lists files with details (permissions, size, modification time).
  • ls -a: Shows hidden files.

• File Manipulation:

  • touch filename.txt: Creates an empty file.
  • mkdir new_folder: Creates a new directory.
  • mv oldname.txt newname.txt: Renames a file.
  • mv file.txt /path/to/destination/: Moves a file.
  • cp file.txt /path/to/destination/: Copies a file.
  • cp -r folder /path/to/destination/: Recursively copies a directory.
  • rm filename.txt: Deletes a file.
  • rm -r foldername: Recursively deletes a directory (use with caution!).

• File Viewing:

  • cat file.txt: Displays file contents.
  • less file.txt: Displays large files page by page (quit with 'q').
  • head file.txt: Displays the first 10 lines of a file.
  • tail file.txt: Displays the last 10 lines of a file.

3. User Management

Commands for adding, managing, and switching users:

• sudo useradd -m username: Adds a new user with a home directory.
• sudo passwd username: Sets a password for a user.
• sudo userdel username: Deletes a user account.
• su - username: Switches to another user's account.
• who: Lists currently logged-in users.

4. Software Installation & Management

Using Pacman and AUR helpers:

• Pacman:

  • sudo pacman -S packagename: Installs a package.
  • sudo pacman -R packagename: Removes a package.
  • sudo pacman -Ss keyword: Searches for packages.
  • pacman -Q: Lists installed packages.
  • pacman -Qi packagename: Shows package information.

• AUR Helper (yay):

  • yay -S packagename: Installs a package from the AUR.
  • yay -Syu: Updates all packages (official repos and AUR).

5. Networking

Essential commands for managing network connections:

• ip addr: Shows network interface information.
• ping -c 4 google.com: Tests internet connectivity.
• nmcli dev wifi connect "SSID" password "your_password": Connects to a Wi-Fi network.
• netstat -tuln: Shows active network connections.
• ip route: Displays routing table.

6. Disk Management

Commands for checking disk usage, partitioning, and managing storage:

• df -h: Shows disk space usage.
• du -sh /path/to/directory: Shows disk usage of a directory.
• sudo mount /dev/sdX1 /mnt: Mounts a partition.
• sudo umount /mnt: Unmounts a partition.
• lsblk: Lists block devices.
• sudo fdisk /dev/sdX: Partitions a disk.
• sudo mkfs.ext4 /dev/sdX1: Formats a partition with ext4.
• sudo smartctl -a /dev/sdX: Checks disk health.
• sudo dd if=/dev/zero of=/swapfile bs=1M count=1024; sudo chmod 600 /swapfile; sudo mkswap /swapfile; sudo swapon /swapfile: Creates a swap file.
• sudo swapoff /swapfile; sudo rm /swapfile: Removes a swap file.

7. Process Management

Commands for viewing and controlling running processes:

• ps aux: Shows running processes.
• top: Displays real-time process information.
• htop: Interactive process viewer (install with sudo pacman -S htop).
• kill PID: Stops a process.
• kill -9 PID: Forcefully stops a process.
• pgrep processname: Finds the PID of a process.
• nice -n 10 command: Runs a command with adjusted priority.
• sudo renice -n 10 -p PID: Changes the priority of a running process.

8. Permissions & Ownership

Commands for managing file permissions and ownership:

• chmod 644 filename: Sets file permissions (numeric mode).
• chmod u x filename: Adds execute permission for the owner (symbolic mode).
• sudo chown username:groupname filename: Changes file ownership.
• sudo chown -R username:groupname directory: Recursively changes ownership of a directory.
• sudo chgrp groupname filename: Changes file group ownership.

9. System Logs & Monitoring

Commands for viewing system logs:

• journalctl: Views system logs.
• journalctl -u servicename: Views logs for a specific service.
• journalctl --since "YYYY-MM-DD": Views logs since a specific date.

10. Troubleshooting

Commands for resolving common issues:

• systemctl rescue: Enters rescue mode.
• sudo pacman -Sc: Cleans the package cache.
• sudo pacman -S packagename: Reinstalls a package.
• sudo fsck /dev/sdX: Checks and repairs a filesystem.
• sudo pacman -Syyu: Fixes package dependencies.
• sudo pacman -S $(pacman -Qdtq): Reinstalls orphaned dependencies.

11. Advanced Tips

• Aliases: Create shortcuts for commands in your .bashrc file (e.g., alias ll='ls -la').
• Backup/Restore (tar): tar -cvzf backup.tar.gz /path/to/directory (backup), tar -xvzf backup.tar.gz (restore).
• Man Pages: Use man commandname to get detailed help for any command.

This cheat sheet provides a foundation for navigating Arch Linux. Remember to consult the Arch Wiki for more comprehensive information.

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