linux_commands.md

Linux Cheat Sheet

OS Shortcuts

• CTRL + ALT + T: Opens the terminal.

• CTRL + ALT + F1: Switch to the first virtual terminal (similar to Ctrl-Alt-Del on Windows).

• CTRL + H (in File Explorer): Display hidden folders (folders starting with .).

Commands

Basic Commands

ls                          # List files in the current directory
cd                          # Change the current directory
pwd                         # Print the current working directory
mkdir                       # Create a new directory
rm                          # Remove files (note: works for empty directories; to remove a folder with all files inside it recursively, use sudo rm -r)
rmdir                       # Remove directories
cp                          # Copy files and directories
mv                          # Move or rename files and directories
touch                       # Create an empty file or update timestamp
cat                         # Concatenate and display file contents
grep                        # Search for a specific pattern in files
find                        # Search for files and directories
which                       # Show the location of an application
source                      # Execute content of a script within the current shell session (.)

System Information

lsblk                           # List all block devices
df -h                            # Disk space usage of all partitions
hostname                        # Display the hostname
sudo fdisk -l                    # Detailed info of all partitions
uname -a                        # Display system information
uname -m                         # Check computer architecture
uname -r                         # Check kernel version
lsb_release -a                   # Check OS version
sudo dpkg --add-architecture i386 # Enable 32-bit architecture on a 64-bit system
sudo e2label /dev/sda2           # Check partition label
free                             # Check available memory (RAM)
which <app name>                 # Find path of application

Permissions, Ownership

chmod <filename>    # Command used to change the permissions of a given file (need params)
chmod a+x           # Add the execute permission (x) for all (a) users on a file
chown                       # Change owner of files and directories
chgrp                       # Change group ownership of files
sudo chmod 700 "$HOME"           # Change permissions of all files in and underneath $HOME

Network Information

ifconfig            # Display network interfaces and their configurations
hostname -I         # Display the local IP address

Process Management

top              # Display a dynamic view of system processes
ps               # Display a snapshot of current processes
kill <pid>       # Terminate a process using its process ID

SSH (Secure Shell)

ssh <username>@<hostname_or_ip>   # Connect to another machine via SSH

Compression and Decompression

tar -czvf <archive_name.tar.gz> <source_directory>          # Create a compressed archive
tar -xzvf <archive_name.tar.gz>                         # Extract a compressed archive
dpkg                        # Low-level package management command - For managing individual .deb packages
dpkg -l                     # List all installed programs
unxz                        # Uncompress .xz files

User Management & Super Root Privileges

sudo su -                   # Switch to root user
sudo passwd root            # Unlock root - adds a new password
sudo passwd -dl root        # Re-lock root
whoami                      # Display the name of the current user                     
sudo adduser <username>     # Add a new user    
sudo userdel <username>     # Delete a user    

Update Commands

sudo apt                    # Package management command to install, update, and remove software packages (apt-get or apt)
sudo apt update             # Check available updates for Linux applications
sudo apt upgrade            # Upgrade updatable Linux applications
apt list --upgradable       # List upgradable content

Environment Variables

echo $HOME                  # User's home directory

Other Commands

code .                      # Open the current directory with VSCode
systemctl                   # Controls and manages system services
ssh                         # Connect to a remote server using SSH

Additional Tips

Use the man command followed by the command name to access manual pages and learn more about each command's options and usage.

Raspberry Pi Commands

Open main configurations

sudo raspi-config

System Reboot and Shutdown

sudo reboot             # Reboot the Raspberry Pi
sudo shutdown -h now    # Shutdown the Raspberry Pi immediately