Mastering The Terminal: All You Need To know.

Hello there. If you’re new to terminal, or if you ever felt uncomfortable using it or if you’re wondering what good learning all this will do to you…then you’re in the right place. In this article I’m gonna walk you through basic terminal commands that will get you started.

For some strange reason I have found that there’s this stigma around the command line and most people think they can get their work done with GUI based applications like Finder (in mac) without ever bothering to learn terminal commands. But I’m here to say using the command line is so much easier and faster than you might think once you get over the learning curve, which in this case is not sky high. If you’re a software developer, you might have stumbled upon some situations where you have no other options but to use the good old command line. Either way, by the end of this article, you will be comfortable with many of the basic unix commands. But first things first, you should see why using the command line is more advantageous for you without just taking my word for it.

So why should you master the command line?

There are endless reasons as to why. But here are few,

1. More Control Over Your Machine.

With the command line you can do a lot of things that are otherwise impossible. You can change permissions of files, view hidden files(which you cannot do with finder), start servers and many more. Basically learning the command line will deepen your relationship with your machine and it will always come in handy.

2. It’s way more faster than using any GUI tool.

This will save a lot of time and make things the way you want it to be with just one line. If you want to make a nested folder structure for an example, it will take you ages if you don’t use the command line. It’s just a matter of executing a one line command through the terminal to create such nested folders and file structure. Typing is way faster than clicking and moving your mouse around.

3. You can automate many tasks.

You can do repetitive tasks with just a single command. You don’t have to suffer through the burden of doing all that manual labour if you know how to use the terminal to your will.

If you want to create a folder with subfolders for each day of the year, imagine the pain of right clicking and making a new folder 365 times and renaming each one of those with the day number. But this is just a one command task with the terminal,

mkdir Day{1..365} 

If you execute this command from your terminal, all of a sudden you will have 365 folders each named with Day1, Day2 and so on.

4. These commands are universal.

You can use any of the unix commands from your ubuntu machine, mac without any problem and with a little bit of work on windows machines.

5. Mastering the command line will really pay off if you’re planning to become a web developer, data scientist, devops engineer, cloud engineer or literally any software related job. This will also come in handy when using version control systems like git. Having a sound knowledge of terminal commands will level you up in your developer journey.

Now that you know why it is important master the terminal, before we get into terminal commands, we have some groundwork to do. That’s understanding the diversity of Operating Systems.

Operating Systems.

Basically, all the operating systems can be roughly divided into two categories.

1. The Microsoft NT descendents like Windows, XBox etc.
2. All the other operating systems pretty much has a lineage going back to Unix. This includes Mac OS, Linux, Android, Chrome OS etc.

If you’re interested in learning about operating system families I highly recommend you to check this article out. But for now, it’s more than enough to be aware of the two different OS families and to which one your machine belongs to. All the commands that I’m about to elaborate are Unix commands which will run on mac and in ubuntu which is a complete linux operating system.

In Windows, there can be different variations because of the different OS family origin. But these commands are mostly universal, which means mastering them will benefit you immensely cross-platform wise.

Unix and Unix Philosophy.

Unix is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in the 1970s at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and others.

Well, that’s what wikipedia has to say about what Unix is. Unix is basically the great-grandparent to many of the different operating systems that we have today. Apart from windows NT descendants, pretty much every other operating system is directly or indirectly descending from Unix.

In the early days of computers, operating systems were tightly bound to hardware. Unix decoupled the two and emphasised upon modular software design which in simpler terms means creating small individual programs which can be clustered together to perform complex tasks.

In this article we’re not going to learn detailed history of Unix but if you’re interested you can check this article out.

The commands which we’re gonna explore are Unix commands which are compatible with true unix OS like mac or unix like operating systems such as ubuntu.

Okay! Now it’s time to hop onto commands!

Basic Unix commands you need to know.

1. ‘pwd’ command — Print Working Directory command

If you open your terminal right now, and type “pwd” and hit enter, you can get to know in which directory you’re in currently. This is one of the most commonly used commands ever. You will get something like this depending on where you are currently.

/Users/navodanilakshi

No matter where you are, the path to your current working directory from the root directory will be printed out to the standard output. Notice the path begins with a “/” and it stands for the root directory. In my case I’m inside my home directory (navodanilakshi) inside Users which is located in root directory.

2. ‘ls’ command

This is probably the most used command you will come across. If you have a terminal tab open, enter ls and hit enter. This will list contents that are in your current working directory. But it wont list down hidden files by default. If you want to list down all the files, including files starting with ‘.’ such as .gitignore, .bash_profile, you need to pass an extra argument to the ls command which is -a.

ls  #this will list directory contents
ls -a  #this will list directory contents including hidden files
ls -l   #this will list in long format

When you use ls -l, you will notice file sizes are depicted like 128,96. These are not very human readable. What you can do to retrieve file sizes in readable formats like 128KB, 96KB is to add -h when you executing the ls -l command and it will look something like this.

ls -lh  

There are tons of arguments like l, a, h that you can pass into the ls command following a dash but these are the most frequently used ones.

3. ‘cd’ command

cd <destination>

Simply, this is used to change the directory to a specified location. If you want to go into some directory you can execute cd command followed with the path to the place where you want to go. That path can be relative or absolute (which means all the way from root directory)

If a path is absolute, then it can take you to that place from anywhere in the system. This is not the case with relative paths. It all depends on which directory you are in.

If you execute ls command and see the directory you want to navigate to, then it means it’s in your current working directory. In this case you can simple use cd followed by the name of the directory. You do not need to specify the path because it’s in the same directory.

cd projects   

The following command will take you to public folder inside projects.

cd projects/public

If you want to navigate to root directory from anywhere on your computer, you can use,

cd /

If you want to navigate to home directory from anywhere on your computer, you can use,

cd ~

If you want to back up a level (go to previous level directory) you can use,

cd ..

4. ‘mkdir’ command

The mkdir utility creates the directories named as operands, in the order specified. You can create a folder in your current working directory by specifying only the folder name after mkdir.

mkdir cats  #this will make a cats folder inside your directory
mkdir cats/kittens #this will make a kittens folder inside cats
mkdir cats dogs rats #this will make 3 folders

If you want to create a folder and another sub folder inside that newly created folder, you can achieve this by adding -p before the folder structure.

mkdir -p mainFolder/subFolder

5. ‘touch’ command

This command is used to make files. This is very similar to mkdir command but this cannot be used to make folders. This is intended to make files.

touch newfile.txt  #This will create a newfile.txt  inside of your current working directory
touch projects/newfile.txt -> This will create a newfile.txt  inside of projects folder

You can also create multiple files at once using the touch command.

touch index.html app.js app.css -> This will create 3 new files(index.html,app.js,app.css)inside of your current working directory

6. ‘rm’ command

This command is used to delete files or folders. It’s used commonly in following ways,

rm <filename>

But that file you specify should be within your current working directory or else you should specify the path: Eg: rm projects/new/hello.txt.

Also, you cannot use just rm followed by folder name to remove folders. Plain rm command will only work for files. So if deleting folders is your intention, then you should add extra arguments to make it possible with rm.

rm -d <foldername>  #This will delete projects folder is it’s empty
rm -r <foldername> #this will recursively delete the specified folder if it’s not empty along with any other files folders inside it.

7. ‘mv’ command

This command is commonly used to move files from one destination to another destination.

mv <file> <destination>

If the destination you specify doesn’t exists, then it will rename the file from what it is, to specified destination name. This makes it possible to use mv command to move files and also to rename them.

mv <current> <new>  #can be used to rename a file
mv new.txt ~  #this will move new.txt which is in your current working directory to home directory
mv <file> ..  #this can be used to move an item to the previous directory

8. ‘cp’ command

This command can be used to copy a file to a given destination.

cp <source> <destination>

Examples:

cp todos moreTodos #this makes a copy of todos called moreTodos in the same location
cp todos ~/newTodos #this makes a copy of todos called newTodos in the home directory

If you’re copying directories add -r to recursively copy any content that’s inside of the directory.

cp -r <folder> <destination>

It’s time to roll up your sleeves and write terminal commands like a pro. Cheers!