Adding the Linux alias Command in the .bashrc File
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The command line terminal is a convenient and fast tool for interfacing with the Linux operating system. However, you may find yourself sending the same commands again and again while issuing instructions to your system. This may cost you a significant amount of time, especially if your commands are lengthy, hard to remember, or just repetitive. To help save time and reduce frustration, aliasing commands can be used to create customizable shortcuts.
This guide covers two ways to alias commands:
- Creating a permanent alias using the
alias
command. - Creating a function for aliases that can accept arguments.
Permanent Alias
There are two ways to create aliases for your use, temporary and permanent. Temporary aliases are only available to use until you close your current terminal session. Permanent aliases are saved to the shell configuration file and are available for every new session you create.
Again, temporary aliases are only good for the current terminal session. Once you close that session, they are no longer available. To make them permanent, you can save your aliases in the shell configuration file. You can read more about temporary aliases in our general guide on aliases, How to Use the Linux alias Command.
In the Bash shell, you can save aliases directly in a configuration file. There are several files you can save aliases to:
- the main Bash configuration file
~/.bashrc
, - a Bash profile file
~/.bash_profile
, - the general shell profile file
~/.profile
, - or you can create a separate aliases file
~/.bash_aliases
.
~/.bashrc
The ~/.bashrc
file is the main configuration file for the Bash shell. When Bash is used as an interactive non-login shell, it uses the ~/.bashrc
file commands. The commands in this file are run every time a new shell is launched.
With your preferred text editor, open the configuration file. Enter one alias per line. While you can add your aliases anywhere in this file, grouping them together makes them easier to reference and adjust.
- File: ~/.bashrc
1 2 3 4 5 6 7
... #aliases alias update="sudo apt update && sudo apt upgrade" alias top="htop" ...
Any newly added aliases are available for use in your next terminal session; they are not immediately available for any current sessions.
If you wish to use them right away in a current session, use the following command:
source ~/.bashrc
~/.bash_profile
When Bash is used as an interactive login shell, ~/.bash_profile
is used. The commands in this file are only run once. This is useful for scripts that you want to run when first logging into your machine directly or via SSH. For scripts that you want to run for every new terminal window you open, use ~/.bashrc
instead. Typically, you would also place commands such as setting $PATH
environment variables in ~/.bash_profile
; setting aliases in this file is common as well.
Setting aliases in ~/.bash_profile
is the same as setting them in ~/.bashrc
.
If you want all the commands in ~/.bashrc
to also be run at login, you can add the following lines to your ~/.bash_profile
file to ensure the ~/.bashrc
file is also run at startup.
- File: ~/.bash_profile
1 2 3 4 5 6 7
... if [ -f ~/.bashrc ]; then . ~/.bashrc fi ...
~/.profile
Commands in ~/.profile
are available to all shells and are not limited to the Bash shell. This file works just like the commands in the ~/.bash_profile
file.
If you find yourself using different shells or ever desire to change shells, put your aliases here.
~/.bash_aliases
If you have a lot of aliases, you may consider creating a separate file just for aliases called ~/.bash_aliases
. This is not a standard configuration file and it is not run by default. To run it you need to reference it from another Bash configuration file like ~/.bashrc
.
- File: ~/.bashrc
1 2 3 4 5 6 7
... if [ -f ~/.bash_aliases ]; then . ~/.bash_aliases fi ...
This if
statement checks for a ~/.bash_aliases
file and runs its contents if the file is present.
If you already have a terminal session open, the aliases are not available until a new session is opened unless you run the following command:
source ~/.bashrc
Exception for MacOS
The macOS terminal app runs a login shell for each new terminal window. Therefore it runs the ~/.bash_profile
for each new terminal instance.
Function Alias with Arguments
If you need to create an alias that accepts arguments, a Bash function is the way to go. These can be placed in any of the above mentioned files. The syntax can be either of the following:
function_name () {
command1
command2
}
This can also be written in one line. However, if you compress it as such, you must use semicolons after each command.
function_name () { command1; command2; }
You can also write a Bash function like this:
function function_name {
command1
command2
}
To use the function with arguments, the syntax is function_name
followed by arguments separated with spaces.
Let’s make a simple function that changes into a specified directory and then lists the directory contents.
- File: ~/.bashrc
1 2 3 4 5 6 7
... function cdl { cd $1 && ls -lah } ...
- The
$1
references the first argument. If you have a function that takes more than one, you use$1
,$2
,$3
, etc. referencing arguments as they appear after the function name when you call the function from the command line. - The
&&
ensures that thels
command only runs if thecd
command was successful. Feel free to use thels
options you prefer here.
To use this function open a new terminal; or, if you want to use an open terminal, you need to first source the shell with the following command:
source ~/.bashrc
Then run the function with the following syntax:
cdl /path/to/directory
You are changed into that directory and get a directory listing with common options with a single command.
These are a simplistic examples meant to illustrate what you can achieve with aliasing. Bash functions are powerful and allow you to do much more complex operations. For more on Bash shell scripting, see the guide series starting with Introduction to Bash Shell Scripting.
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