Common Linux Commands and Descriptions
File and Directory Operations
-
ls– Lists the contents of a directory.ls ls -l # Long listing format ls -a # List all files, including hidden ones -
cd– Changes the current directory.cd /path/to/directory cd .. # Go up one directory cd ~ # Go to the home directory -
mkdir– Creates a new directory.mkdir new_directory -
rmdir– Removes an empty directory.rmdir directory_name -
cp– Copies files or directories.cp source_file destination cp -r source_directory destination_directory # Copy directories recursively -
mv– Moves or renames files and directories.mv old_name new_name mv file_name /path/to/destination/ -
rm– Removes files or directories.rm file_name rm -r directory_name # Remove directories recursively -
touch– Creates an empty file or updates the timestamp of an existing file.touch file_name
File Viewing & Manipulation
-
cat– Displays the contents of a file.cat file_name -
less– Allows you to view file contents page by page.less file_name -
head– Shows the first 10 lines of a file (default).head file_name head -n 5 file_name # Show the first 5 lines -
tail– Shows the last 10 lines of a file (default).tail file_name tail -n 5 file_name # Show the last 5 lines -
grep– Searches for patterns within files.grep 'search_term' file_name grep -r 'search_term' /path/to/directory # Search recursively in directories
Permissions & Ownership
-
chmod– Changes file permissions.chmod 755 file_name # Gives read, write, execute permissions to the owner and read, execute to others chmod +x script.sh # Make file executable -
chown– Changes the file owner and group.chown user:group file_name -
umask– Sets default file creation permissions.umask 022 # Sets default permissions to 755 for directories and 644 for files
Process Management
-
ps– Displays the currently running processes.ps ps aux # Show all processes -
top– Displays real-time system processes and resource usage.top -
kill– Terminates a process by its PID.kill process_id kill -9 process_id # Forcefully kill a process -
htop– Interactive process viewer (requires installation).htop
System Information
-
df– Shows disk space usage.df -h # Human-readable format -
du– Shows disk usage for files and directories.du -h /path/to/directory -
free– Displays memory usage.free -h # Human-readable format -
uname– Shows system information.uname -a # Display all system info -
uptime– Shows how long the system has been running.uptime -
whoami– Displays the current logged-in user.whoami -
hostname– Displays or sets the system's hostname.hostname -
lscpu– Displays CPU architecture information.lscpu
Network Commands
-
ping– Tests connectivity to a host.ping google.com -
ifconfig– Displays network interface information (may require net-tools installation on some systems).ifconfig -
ip– Configures network interfaces and routing.ip addr show # Show IP addresses of network interfaces ip route show # Show routing table -
curl– Fetches data from a URL.curl https://example.com -
wget– Downloads files from the web.wget https://example.com/file.zip
Package Management
-
apt-get(for Debian/Ubuntu-based distributions) – Installs, updates, or removes software packages.sudo apt-get update # Update package list sudo apt-get install package # Install a package sudo apt-get remove package # Remove a package -
yum(for RedHat/CentOS-based distributions) – Installs, updates, or removes software packages.sudo yum update # Update package list sudo yum install package # Install a package sudo yum remove package # Remove a package
File Compression
-
tar– Archives or extracts files.tar -czvf archive_name.tar.gz /path/to/directory # Create a compressed archive tar -xzvf archive_name.tar.gz # Extract a compressed archive -
zip– Compresses files into a zip archive.zip archive_name.zip file1 file2 -
unzip– Extracts a zip archive.unzip archive_name.zip
Miscellaneous
-
echo– Prints a message or variables to the terminal.echo "Hello, World!" -
date– Displays or sets the system date and time.date -
alias– Creates an alias for a command.alias ll='ls -la' # Create a shortcut for 'ls -la' -
history– Shows the command history.history -
clear– Clears the terminal screen.clear
These are just a few of the many powerful commands in Linux, but they cover most of the common operations you'll perform daily.