004-basic-shell-commands.md

Basic Shell Commands

As throughout this eBook, we will be using mainly Git via the command line. It is important to know basic shell commands so that you could find your way around the terminal.

So before we get started, let's go over a few basic shell commands!

The ls command

The ls command allows you to list the contents of a folder/directory. All that you need to do in order to run the command is to open a terminal and run the following:

ls

The output will show you all of the files and folders that are located in your current directory. In my case, starting from the root directory of this project, the output is the following:

CONTRIBUTING.md LICENSE README.md ebook index.html

From the output, we can see that CONTRIBUTING.md, LICENSE, README.md, index.html are files, while ebook is a subdirectory/subfolder.

For more information about the ls command, make sure to check out this page here.

Note: This will work on a Linux/UNIX based systems. If you are on Windows and if you are using the built-in CMD, you would have to use the dir command.

The cd command

The cd command stands for Change Directory and allows you to navigate through the filesystem of your computer or server. Let's say that I wanted to go inside the ebook directory from the output above. What I would need to do is to run the cd command followed by the directory that I want to access:

cd ebook

If I wanted to go back one level up, I would use the cd .. command. After doing so, I should be one level up from the ebook directory and back in the root directory of my project.

The pwd command

The pwd command stands for Print Working Directory which essentially means that when you run the command, it will show you the current directory that you are in.

Let's take the example from above. If I run the pwd command, I would get the full path to the folder that I'm currently in:

pwd

Output:

/home/bobby/introduction-to-git

Then I could use the cd command and access the ebook directory:

cd ebook

And finally, if I was to run the pwd command again, I would see the following output:

/home/bobby/introduction-to-git/ebook

Essentially what happened was that thanks to the pwd command, I was able to see that I'm at the /home/bobby/introduction-to-git directory and then after accessing the ebook directory, again by using pwd I was able to see that my new current directory is /home/bobby/introduction-to-git/ebook.

The rm command

The rm command stands for remove and allows you to delete files and folders. Let's say that I wanted to delete the README.md file, what I would have to do is run the following command:

rm README.md

In case that I had to delete a folder/directory, I would need to specify the -r flag:

rm -r ebook

Note: keep in mind that the rm command would completely delete the files and folders, and the action is irreversible, meaning that you can't get them back.

The mkdir command

The mkdir command stands for make directory and is used for creating one or more new directories. All you need to do in order to create a new directory using this command is to open a terminal, cd into desired location and run the following:

mkdir My_New_Directory

The above command will create a new, empty directory called My_New_Directory.

You can also create serveral new directories by placing the names of desired directories after each other:

mkdir My_New_Directory My_Another_New_Directory

The touch command

The touch command is used to update timestamps on files. A useful feature of the touch command is that it will create an empty file. This is useful if you want to create file in your directory that doesn't currently exist:

touch README.md

The above will create a new, empty file with the name README.md

One thing that you need to keep in mind is that all shell commands are case sensitive, so if you type LS it would not work.

With that, now you know some basic shell commands which will be beneficial for your day-to-day activities.