BASH Programming System Administration

Some Useful Bash Aliases and How to Create Bash Aliases

Do you spend a good amount of time working in the command line? Then you may have noticed that most of the commands you run are a small subset of all the available commands. Most of them are habitual and you may be running them every single day.

To lessen the suffering of typing, developers the command utilities have attempted to eliminate the extraneous typing with abbreviations, for example, “ls” instead of “list”, “cd” instead of “change-directory”, “cat” instead of “catenate” etc. Yet, typing the same command over and over and over is truly boring and unenjoyable.

This is where aliases come handy. Using an alias, it’s possible to assign your shortcut for a specific command. Here, we’ll be talking about how to create Bash aliases and demonstrate some useful aliases that you might enjoy.

Bash alias

When you run a command in the terminal, it’s the job of the shell to process and presents it to the OS to do the target job. Bash (acronym of “Bourne-Again shell) is, by far, one of the most popular UNIX shells out there. Most of the Linux distros come with Bash shell by default.

Now, what’s a Bash alias? We all have an idea of how an alias works, right? Similarly, when you want to use your phrase to denote a certain command, you can create an “alias” for that command. Bash will remember and treat the custom phrase as a command. When run, Bash will automatically translate it into the original command.

There are 2 types of Bash aliases.

  • Temporary: This type of alias lasts as long as the shell session is running. Once the shell is terminated, it’ll forget the alias.
  • Permanent: Once created, Bash will remember the creation of the alias and its meaning.

I will show next in this tutorial how to create and manage aliases.  All these methods described are performed on Ubuntu. However, they’ll work on any Linux distro as long as you’re working with Bash.

Temporary Alias Creation

This is the form of an alias that Bash will forget once the session is closed. That’s why I recommend that you create an alias that’s worthwhile for the session.

For creating a temporary Bash alias, the command structure looks like this.

$ alias <alias_name>=<command>

Let’s make it clear with an example. I’m on Ubuntu, so if I want to update all the packages of the system, I have to run the following command.

$ sudo apt update && sudo apt upgrade -y

Now, how about using “apt-sysupdate” as an alternative that’ll do the same job as the aforementioned command? Create the alias by running this command.

$ alias apt-sysupdate="sudo apt update && sudo apt upgrade -y"

Let’s check out if it works!

Voila! It’s working!

Here, whenever Bash sees the command “apt-sysupdate”, it’s going to be translated into the long command that’s going to be executed.

Here’s a fun thing to do. How about we create an alias of an alias? Let’s create the alias “update” for the command “apt-sysupdate”.

$ alias update="apt-sysupdate"

Now, let’s see if it works.

Yup, it does!

Permanent Alias Creation

For creating permanent aliases, we need to declare it in the bashrc file. The bashrc is a shell script that’s executed every time a bash session starts. It’s located at “~/.bashrc”. It’s unique to every single user in the system.

The bashrc is a popular choice for creating your favorite aliases. Bashrc may or may not be present in your system. Open the bashrc with vim. If not present, vim will open an empty text. Learn more about vim.

$ vim ~/.bashrc

Here’s now the code for an alias looks like.

$ alias <alias_name>="<command>"

Let’s create a permanent alias “update” that’ll tell APT to update the repo cache and install all the available updates.

$ alias update="sudo apt update && sudo apt upgrade -y"

Once the alias is created, save the file. Then, tell bash to reload the file.

$ source ~/.bashrc

It’s time to check if it works. Reboot your system, log in to your account, and run the “update” alias we just created.

Voila! The alias is successfully created!

What’s happening here? Simply put, bash is creating a temporary alias every single time the bashrc is loaded. When bash terminates, it forgets the alias. However, as the bashrc file is the first script that bash executes, the temporary alias is back again. It could be described as “pseudo-permanent” alias.

Overriding alias

Let’s say you’ve set an alias “ls” for the command “ls -lhA” and for some reason, you need to use the main “ls” tool to do something different. In similar cases, bypassing an alias is required.

To temporarily bypass an alias, run the command with the following structure.

$ \<command>

For example, I’ve created an alias “ls” for the command “ls -lhA”. Whenever I run ls, it’ll be translated into the command. What if I just want to run the “ls” tool without any additional options? Let’s bypass the alias temporarily.

$ \ls

Listing aliases

To view all the currently configured aliases, run this command.

$ alias

Deleting Temporary Aliases

Removing a temporary alias is super simple. Just run this command.

$ unalias <alias_name>

For example, I have 3 aliases in total. To get rid of the “update” alias, the command would be:

$ unalias update

Let’s verify the result.

$ alias

Voila! Alias is gone!

Another way is to lot out of the current bash session or rebooting the system. Bash won’t remember the temporary aliases. Here, I’ve rebooted my computer and there’s no bash alias.

Deleting Permanent aliases

The aliases that are declared in the bashrc file won’t go away. Even if you unalias them, they’re not removed from the bashrc file. Next time the bash session is loaded, the alias is also back. That’s why to get rid of a permanent alias, we have to manually remove them from the bashrc file.

Open the bashrc file in vim.

$ vim ~/.bashrc

Remove the bash aliases you don’t need. Alternatively, you can comment them out so that next time you need them, you can simply uncomment.

Save the file and tell bash to reload bashrc.

$ source ~/.bashrc

Some useful bash aliases

Here are some common aliases that many people use. Feel free to experiment with aliases. Remember, anytime you forget an alias, you can just run the “alias” command to see which one to run.

The following command will print the directory content with human-readable information in a “long listing” format.

$ alias ll="ls -lha"

Let’s make “ls” to display entries in a column with indicators.

$ alias ls="ls -CF"

We can also make a typo run the intended command.

$ alias sl="ls -Cf"

Sometimes, the ls output will be very long. In such a situation, let’s pipe the output of ls to less.

$ alias lsl="ls -lhFA | less"

Next up, it’s the “cd” command. Let’s add an alias to back to the parent directory.

$ alias ..="cd .."

Use the next alias to search for your desired file/folder in the current directory.

$ alias fhere="find . -name "

Now, let’s check out some system aliases. The “df” tool is used for checking out the disk usage. Set the following alias so that it reports the output in the human-readable unit along with filesystem type and print total at the bottom.

$ alias df="df -Tha --total"

How about reconstructing the “du” tool output?

$ alias du="du -ach | sort -h"

The “free” tool reports the amount of used/unused memory of the running system. Let’s make the “free” output friendlier.

$ alias free="free -mt"

If you’re constantly working with the process table, there are many aliases we can implement. For example, let’s set out a default output for the command “ps”.

$ alias ps="ps auxf"

Let’s add a search function to the process table.

$ alias psg="ps aux | grep -v grep | grep -i -e VSZ -e"

How about making a directory/folder a little easier? Often, “mkdir” is followed by the “-p” flag for making any necessary parent directory. Let’s bind it in the following alias.

$ alias mkdir="mkdir -p"

Want to get notified of every directory creation? Let’s add the “-v” flag with “mkdir”.

$ alias mkdir="mkdir -pv"

Wget is a simple command-line downloader. However, if it faces any problem during download, it’ll cancel automatically. To force wget to continue downloading, the “-c” flag has to be passed. Let’s combine them in this alias.

$ alias wget="wget -c"

Need to check out the public IP address? Let’s add it to the alias list!

$ alias myip="curl http://ipecho.net/plain; echo"

Here’s how my bashrc looks with all these aliases.

Final thoughts

Alias is a wonderful feature that lessens the burden and boredom of typing the same long command. It’s also extremely useful in using bash scripts to lessen the workload while the code remains free from unnecessary clutter.

There’s no fixed set of aliases. The aliases I mentioned before are some common ones that experts always use. However, depending on your day-to-day work, you’ll eventually come up with your own aliases.

If you’re using a lot of aliases, I recommend keeping them together in the bashrc file with necessary commenting.

Enjoy!

About the author

Sidratul Muntaha

Sidratul Muntaha

Student of CSE. I love Linux and playing with tech and gadgets. I use both Ubuntu and Linux Mint.