Commonly Used Linux Commands
Update
| Command | Description |
|---|---|
apt update |
Fetches only the information on latest packages that can be upgraded |
apt list –upgradable |
Display the packages that have updates available and therefore can be upgraded on the system. |
apt upgrade |
The actual command that does the upgrade of the packages in the system. This command can install new packages if the dependencies require it, but it will never remove packages. |
apt full-upgrade |
In addition to upgrading new packages and installing new packages as required, it also removes existing installed packages if it determines that the dependencies are no longer required. |
apt autoremove |
Removes unused packages which are no longer needed by the dependent packages. This can be executed after apt upgrade |
Files and Directories
| Command | Description |
|---|---|
pwd |
Shows Present Working Directory |
ls |
List all files, directories in the current working directory (Doesn't list hidden/dot files) |
ls -a |
List all files, directories in the current working directory including the hidden/dot files |
ls -al |
List all files, directories in the current working directory including the hidden/dot files with additional details |
cd |
Navigates back to home directory |
cat [FILE_NAME] |
Displays the contents of the file |
echo "[TEXT]" |
Displays the TEXT on the screen |
echo "[TEXT]" -> [FILE_NAME.FILE_FORMAT] |
save the TEXT in a with the given FILE_NAME and FILE_FORMAT |
touch [FILE_NAME.FILE_FORMAT] |
Creates a new file with the given FILE_NAME and FILE_FORMAT |
mkdir [DIRECTORY_NAME] |
Creates a new directory with the given DIRECTORY_NAME |
rmdir [DIRECTORY_NAME] |
Removes the directory with the given DIRECTORY_NAME |
rm [FILE_NAME] |
Removes the file with the given FILE_NAME |
lsblk -f |
displays block devices, when used with the -f option, it prints file system type on partitions as well |
nano [FILE_NAME.FILE_FORMAT] |
Creates a new file with the given FILE_NAME and FILE_FORMAT in nano text editor. |
sed -i '/old text/ s//new text/g' file_name.extension |
Replace text in a file. |
Various
| Command | Description |
|---|---|
printenv or env |
List all the environment variables |
cat /proc/cpuinfo |
Display CPU info |
find the number of physical CPU cores |
find the number of physical CPU cores |
Processes
| Command | Description |
|---|---|
ps |
Lists current user's running processes |
ps aux |
Lists all running processes |
ps aux | grep $USER |
show all running processes, but limit the output to lines containing your username |
Others
| Command | Description |
|---|---|
history |
Lists recently used commands |
date |
Shows current date and time |
cal |
Shows calendar view of the current month |
lsb_release -a |
Check the Ubuntu version |
reboot |
Restart/Reboot the computer |
sudo poweroff |
shut down the system |
cat /etc/lsb-release |
prints distro information |
whereis grub |
points to the location of grub |
dpkg --print-architecture |
|
hostnamectl |
System
| Command | Description |
|---|---|
uname -a |
Prints system information like kernel release date, version, processor type, etc |
uname -sr |
returns system information |
uname -m |
|
who |
Shows the logged-in user |
whoami |
Shows the current user's username |
who | wc -l |
Displays the count of users currently logged in. |
Others
- ls – The most frequently used command in Linux to list directories
- pwd – Print working directory command in Linux
- cd – Linux command to navigate through directories
- mkdir – Command used to create directories in Linux
- mv – Move or rename files in Linux
- cp – Similar usage as mv but for copying files in Linux
- rm – Delete files or directories
- touch – Create blank/empty files
- ln – Create symbolic links (shortcuts) to other files
- cat – Display file contents on the terminal
- clear – Clear the terminal display
- echo – Print any text that follows the command
- less – Linux command to display paged outputs in the terminal
- man – Access manual pages for all Linux commands
- uname – Linux command to get basic information about the OS
- whoami – Get the active username
- tar – Command to extract and compress files in Linux
- grep – Search for a string within an output
- head – Return the specified number of lines from the top
- tail – Return the specified number of lines from the bottom
- diff – Find the difference between two files
- cmp – Allows you to check if two files are identical
- comm – Combines the functionality of diff and cmp
- sort – Linux command to sort the content of a file while outputting
- export – Export environment variables in Linux
- zip – Zip files in Linux
- unzip – Unzip files in Linux
- ssh – Secure Shell command in Linux
- service – Linux command to start and stop services
- ps – Display active processes
- kill and killall – Kill active processes by process ID or name
- df – Display disk filesystem information
- mount – Mount file systems in Linux
- chmod – Command to change file permissions
- chown – Command for granting ownership of files or folders
- ifconfig – Display network interfaces and IP addresses
- traceroute – Trace all the network hops to reach the destination
- wget – Direct download files from the internet
- ufw – Firewall command
- iptables – Base firewall for all other firewall utilities to interface with
- apt, pacman, yum, rpm – Package managers depending on the distro
- sudo – Command to escalate privileges in Linux
- cal – View a command-line calendar
- alias – Create custom shortcuts for your regularly used commands
- dd – Majorly used for creating bootable USB sticks
- whereis – Locate the binary, source, and manual pages for a command
- whatis – Find what a command is used for
- top – View active processes live with their system usage
- useradd and usermod – Add new user or change existing users data
- passwd – Create or update passwords for existing users
