Linux Cheatsheets

advanced.md

Linux Cheat Sheet for Advanced Users

Scripting and Automation

• Write a bash script: Create a file with #!/bin/bash at the top and script contents.
• Execute a bash script: bash [script_file]
• Schedule a cron job: crontab -e and add line [minute] [hour] [day_of_month] [month] [day_of_week] [command]

Server Setup and Management

• Install packages (Debian/Ubuntu): apt-get install [package]
• Install packages (RedHat/CentOS): yum install [package] or dnf install [package]
• Start/stop a service: systemctl start [service] or systemctl stop [service]
• Enable/disable a service at boot: systemctl enable [service] or systemctl disable [service]

System Security

• Change file access control lists: setfacl -m u:[user]:[permissions] [file]
• Firewall management (iptables): iptables [options]
• Scan for vulnerabilities (with nmap): nmap -sV -T4 -O -F --version-light [target]

Kernel and System Performance

• Display kernel messages: dmesg
• Modify kernel parameters at runtime: sysctl -w [parameter]=[value]
• Monitor system performance: vmstat, iostat
• Check available entropy: cat /proc/sys/kernel/random/entropy_avail

Network Troubleshooting

• Trace route to host: traceroute [host]
• Monitor network traffic: tcpdump [options]
• Analyze network performance: iperf3 -s (server) and iperf3 -c [server_ip] (client)

Note: Replace [script_file], [package], [service], [user], [permissions], [file], [options], [target], [parameter], [value], [host], and [server_ip] with your specific details.

arch_and_manjaro.md

Arch Linux and Manjaro Cheat Sheet

Arch Linux Package Management (Pacman)

• Synchronize and update packages: sudo pacman -Syu
• Install a package: sudo pacman -S [package]
• Remove a package and its dependencies: sudo pacman -Rs [package]
• Search for a package: pacman -Ss [package]
• List installed packages: pacman -Q

AUR (Arch User Repository) - Common for Arch and Manjaro

• Install an AUR helper (like yay): git clone [yay_repo_url], then build and install with makepkg -si
• Install a package from AUR: yay -S [package]

System Configuration for Arch

• Edit the mirror list: sudo nano /etc/pacman.d/mirrorlist
• Update the system's locale: sudo nano /etc/locale.gen then sudo locale-gen
• Set the timezone: sudo timedatectl set-timezone [timezone]

Manjaro Specific Package Management (Pamac)

• Update system: pamac update
• Install a package: pamac install [package]
• Remove a package: pamac remove [package]
• Search for a package: pamac search [package]

System Services (systemd) - Common for Arch and Manjaro

• Start a service: sudo systemctl start [service]
• Enable a service to start at boot: sudo systemctl enable [service]
• Check the status of a service: systemctl status [service]

Note: Replace [package], [yay_repo_url], [service], [timezone] with your specific details.

beginner.md

Linux Cheat Sheet for Beginners

Basic Navigation

• List files and directories: ls
• Change directory: cd [directory]
• Print current directory: pwd
• Display contents of a file: cat [file]

File and Directory Operations

• Create a new file: touch [file]
• Create a new directory: mkdir [directory]
• Copy files or directories: cp [source] [destination]
• Move/rename files or directories: mv [source] [destination]
• Delete a file: rm [file]
• Delete a directory: rm -r [directory]

Viewing and Editing Files

• Open a file in a text editor (Nano): nano [file]
• Open a file in a text editor (Vim): vim [file]
• Display the beginning of a file: head [file]
• Display the end of a file: tail [file]
• Search within a file: grep '[pattern]' [file]

System Information and Management

• Display system date and time: date
• Display disk usage: df
• Display free memory: free
• Shutdown the system: shutdown now
• Reboot the system: reboot

Note: Replace [file], [directory], and [pattern] with your specific details.

debian_and_ubuntu.md

Debian and Ubuntu Linux Cheat Sheet

Common Package Management (APT)

• Update package list: sudo apt update
• Upgrade all packages: sudo apt upgrade
• Install a package: sudo apt install [package]
• Remove a package: sudo apt remove [package]
• Search for a package: apt search [package]

System Services (systemd)

• Start a service: sudo systemctl start [service]
• Stop a service: sudo systemctl stop [service]
• Enable a service to start at boot: sudo systemctl enable [service]
• Disable a service from starting at boot: sudo systemctl disable [service]

User Management

• Add a new user: sudo adduser [username]
• Delete a user: sudo deluser [username]
• Add a user to a group: sudo usermod -aG [group] [username]

Networking

• Debian - Edit network configuration: sudo nano /etc/network/interfaces
• Ubuntu - Edit network configuration: sudo nano /etc/netplan/*.yaml then apply with sudo netplan apply
• Assign IP address with DHCP: sudo dhclient [interface]
• Display network configuration: ip addr

Ubuntu Specific

• Use Snap for package management: sudo snap install [package]
• List Snap packages: snap list
• Remove Snap package: sudo snap remove [package]

Note: Replace [package], [service], [username], [group], [interface] with your specific details.

fedora_and_rhel.md

Fedora and Red Hat Enterprise Linux (RHEL) Cheat Sheet

Package Management (DNF for Fedora, YUM for RHEL)

• Fedora - Update package list and upgrade: sudo dnf update
• RHEL - Update package list and upgrade: sudo yum update
• Install a package: sudo dnf install [package] or sudo yum install [package]
• Remove a package: sudo dnf remove [package] or sudo yum remove [package]
• Search for a package: dnf search [package] or yum search [package]

System Services (systemd)

• Start a service: sudo systemctl start [service]
• Stop a service: sudo systemctl stop [service]
• Enable a service to start at boot: sudo systemctl enable [service]
• Disable a service from starting at boot: sudo systemctl disable [service]

User Management

• Add a new user: sudo useradd [username]
• Delete a user: sudo userdel [username]
• Add a user to a group: sudo usermod -aG [group] [username]

SELinux Management

• Check SELinux status: sestatus
• Change file or directory SELinux context: sudo chcon -t [context_type] [file_or_directory]
• Manage SELinux booleans: sudo setsebool [boolean_name] [on|off]

Networking

• Assign IP address with DHCP: sudo dhclient [interface]
• Display network configuration: nmcli d
• Edit network configuration: sudo nmtui

RHEL Specific

• Register with Red Hat Subscription Manager: sudo subscription-manager register
• Attach a subscription: sudo subscription-manager attach --auto

Note: Replace [package], [service], [username], [group], [interface], [context_type], [file_or_directory], [boolean_name] with your specific details.

intermediate.md

Linux Cheat Sheet for Intermediate Users

System Monitoring

• Display active processes: top or htop
• Monitor system logs: tail -f /var/log/syslog (Debian/Ubuntu) or /var/log/messages (RedHat/CentOS)
• Display disk usage: df -h
• Check memory usage: free -m
• List processes: ps aux

Network Commands

• Display network configuration: ifconfig or ip addr
• Ping a host: ping [host]
• Scan network with nmap: nmap [options] [host]
• Display listening ports: netstat -tuln or ss -tuln

Process Management

• Kill a process: kill [pid] or killall [process_name]
• Change priority of a running process: renice [nice_value] [pid]
• Start a job in the background: [command] &
• Bring a job to the foreground: fg [job_number]

User and Group Management

• Add a new user: useradd [username]
• Change user password: passwd [username]
• Add a user to a group: usermod -aG [group] [username]
• Create a new group: groupadd [groupname]
• List groups of a user: groups [username]

File Permissions and Ownership

• Change file permissions: chmod [permissions] [file]
  • Examples:
    • chmod 755 [file]: rwx for owner, rx for group and others.
    • chmod 644 [file]: rw for owner, r for group and others.
• Change file owner: chown [user]:[group] [file]
• Change group ownership of a file: chgrp [group] [file]
• Set sticky bit on a directory: chmod +t [directory]

Note: Replace [host], [options], [pid], [process_name], [command], [job_number], [username], [group], [groupname], [permissions], [file], and [directory] with your specific details.