How to Use Alias in Linux and Ubuntu

An alias in Linux or Ubuntu is a shortcut for a command. It lets you type a short command and have the shell run a longer command for you.

For example, if you often run ls -l to see a detailed file listing, you can make ls run ls -l --color=auto instead. This saves typing and makes common terminal work faster.

Aliases are especially useful for commands you run every day, such as directory listings, server checks, log viewing, Git commands, and script folders.

Check the Current Folder

Start by moving into a folder and listing its files.

This example uses a sample server script folder:

cd /srv/admin/scripts/site-tools
ls

Example output:

Check-Backups.sh  Server-Inventory.sh

The normal ls command shows the file names, but it does not show details such as permissions, owner, file size, or modified date.

Run `ls -l` Manually

To see the long listing format, run:

ls -l

Example output:

total 20
-rwxrwxr-x 1 admin admin  4569 Jul  2 00:41 Check-Backups.sh
-rwxrwxr-x 1 admin admin 11641 Jul  2 00:41 Server-Inventory.sh

This output shows more useful information:

• File permissions, such as -rwxrwxr-x.
• Number of links.
• File owner and group.
• File size.
• Last modified date and time.
• File name.

If you always want this detailed view, you can create an alias.

Create a Temporary Alias

Run this command:

alias ls='ls -l'

Now run:

ls

Example output:

total 20
-rwxrwxr-x 1 admin admin  4569 Jul  2 00:41 Check-Backups.sh
-rwxrwxr-x 1 admin admin 11641 Jul  2 00:41 Server-Inventory.sh

Now the short command ls runs ls -l.

This alias is temporary. It only works in the current terminal session. If you close the terminal or log out, the alias is gone.

Make the Alias Permanent

To keep the alias after logging out, add it to your ~/.bashrc file.

Use this command:

echo "alias ls='ls -l --color=auto'" >> ~/.bashrc

Then reload the file:

source ~/.bashrc

Now run:

ls

Example output:

total 20
-rwxrwxr-x 1 admin admin  4569 Jul  2 00:41 Check-Backups.sh
-rwxrwxr-x 1 admin admin 11641 Jul  2 00:41 Server-Inventory.sh

The --color=auto option keeps normal color output when your terminal supports it. This makes executable scripts, directories, and other file types easier to spot.

View Existing Aliases

To see all aliases currently loaded in your shell, run:

alias

To check one alias, run:

alias ls

Example output:

alias ls='ls -l --color=auto'

Remove an Alias

To remove an alias from the current terminal session, use unalias.

Example:

unalias ls

After that, ls goes back to its normal behavior for the current session.

If the alias is saved in ~/.bashrc, open that file and remove the alias line:

nano ~/.bashrc

Remove or comment out this line:

alias ls='ls -l --color=auto'

Then reload the file:

source ~/.bashrc

Useful Alias Examples

Here are a few common aliases for Linux and Ubuntu.

Show all files in long format:

alias ll='ls -la --color=auto'

Show disk space in human-readable format:

alias dfh='df -h'

Show folder sizes in the current directory:

alias duh='du -h --max-depth=1'

Clear the terminal:

alias c='clear'

Go up one directory:

alias ..='cd ..'

View recent system logs on systems that use journalctl:

alias logs='journalctl -xe'

Edit `.bashrc` Directly

If you plan to add several aliases, it is cleaner to edit ~/.bashrc directly:

nano ~/.bashrc

Add your aliases near the bottom:

alias ls='ls -l --color=auto'
alias ll='ls -la --color=auto'
alias dfh='df -h'
alias c='clear'

Save the file, then reload it:

source ~/.bashrc

You do not need to reboot. Reloading ~/.bashrc applies the aliases to the current terminal.

Important Notes

• Aliases only affect the shell where they are loaded.
• A temporary alias disappears when you close the terminal.
• A permanent alias should be saved in ~/.bashrc.
• Use quotes around the command when creating an alias.
• Be careful when aliasing common commands such as rm, cp, mv, or ls.
• If an alias does not work, run source ~/.bashrc or open a new terminal.

Quick Reference

Create a temporary alias:

alias ls='ls -l'

Make it permanent:

echo "alias ls='ls -l --color=auto'" >> ~/.bashrc
source ~/.bashrc

Check the alias:

alias ls

Remove it from the current session:

unalias ls

Aliases are a simple way to make Linux and Ubuntu commands faster, shorter, and easier to remember. Once you start using them for repeated commands, the terminal feels much more comfortable.