10 commands every Linux user should know

Start mastering the Linux CLI with these 10 fundamental commands.
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401 readers like this
Terminal view

Jamie Cox. Modified by Opensource.com. CC BY 2.0.

You may think you're new to Linux, but you're really not. There are 3.74 billion global internet users, and all of them use Linux in some way since Linux servers power 90% of the internet. Most modern routers run Linux or Unix, and the TOP500 supercomputers also rely on Linux. If you own an Android smartphone, your operating system is constructed from the Linux kernel.

In other words, Linux is everywhere.

But there's a difference between using Linux-based technologies and using Linux itself. If you're interested in Linux, but have been using a PC or Mac desktop, you may be wondering what you need to know to use the Linux command line interface (CLI). You've come to the right place.

The following are the fundamental Linux commands you need to know. Each is simple and easy to commit to memory. In other words, you don't have to be Bill Gates to understand them.

1. ls

You're probably thinking, "Is what?" No, that wasn't a typographical error – I really intended to type a lower-case L. ls, or "list," is the number one command you need to know to use the Linux CLI. This list command functions within the Linux terminal to reveal all the major directories filed under a respective filesystem. For example, this command:

ls /applications

shows every folder stored in the applications folder. You'll use it to view files, folders, and directories.

All hidden files are viewable by using the command ls -a.

2. cd

This command is what you use to go (or "change") to a directory. It is how you navigate from one folder to another. Say you're in your Downloads folder, but you want to go to a folder called Gym Playlist. Simply typing cd Gym Playlist won't work, as the shell won't recognize it and will report the folder you're looking for doesn't exist. To bring up that folder, you'll need to include a backslash. The command should look like this:

cd Gym\ Playlist

To go back from the current folder to the previous one, you can type in the folder name followed by cd ... Think of the two dots like a back button.

3. mv

This command transfers a file from one folder to another; mv stands for "move." You can use this short command like you would drag a file to a folder on a PC.

For example, if I create a file called testfile to demonstrate all the basic Linux commands, and I want to move it to my Documents folder, I would issue this command:

mv /home/sam/testfile /home/sam/Documents/

The first piece of the command (mv) says I want to move a file, the second part (home/sam/testfile) names the file I want to move, and the third part (/home/sam/Documents/) indicates the location where I want the file transferred.

4. Keyboard shortcuts

Okay, this is more than one command, but I couldn't resist including them all here. Why? Because they save time and take the headache out of your experience.

CTRL+K Cuts text from the cursor until the end of the line

CTRL+Y Pastes text

CTRL+E Moves the cursor to the end of the line

CTRL+A Moves the cursor to the beginning of the line

ALT+F Jumps forward to the next space

ALT+B Skips back to the previous space

ALT+Backspace Deletes the previous word

CTRL+W Cuts the word behind the cursor

Shift+Insert Pastes text into the terminal

Ctrl+D Logs you out

These commands come in handy in many ways. For example, imagine you misspell a word in your command text:

sudo apt-get intall programname

You probably noticed "install" is misspelled, so the command won't work. But keyboard shortcuts make it easy to go back and fix it. If my cursor is at the end of the line, I can click ALT+B twice to move the cursor to the place noted below with the ^ symbol:

sudo apt-get^intall programname

Now, we can quickly add the letter s to fix install. Easy peasy!

5. mkdir

This is the command you use to make a directory or a folder in the Linux environment. For example, if you're big into DIY hacks like I am, you could enter mkdir DIY to make a directory for your DIY projects.

6. at

If you want to run a Linux command at a certain time, you can add at to the equation. The syntax is at followed by the date and time you want the command to run. Then the command prompt changes to at> so you can enter the command(s) you want to run at the time you specified above

For example:

at 4:08 PM Sat
at> cowsay 'hello'
at> CTRL+D

This will run the program cowsay at 4:08 p.m. on Saturday night.

7. rmdir

This command allows you to remove a directory through the Linux CLI. For example:

rmdir testdirectory

Bear in mind that this command will not remove a directory that has files inside. This only works when removing empty directories.

8. rm

If you want to remove files, the rm command is what you want. It can delete files and directories. To delete a single file, type rm testfile, or to delete a directory and the files inside it, type rm -r.

9. touch

The touch command, otherwise known as the "make file command," allows you to create new, empty files using the Linux CLI. Much like mkdir creates directories, touch creates files. For example, touch testfile will make an empty file named testfile.

10. locate

This command is what you use to find a file in a Linux system. Think of it like search in Windows. It's very useful if you forget where you stored a file or what you named it.

For example, if you have a document about blockchain use cases, but you can't think of the title, you can punch in locate -blockchain or you can look for "blockchain use cases" by separating the words with an asterisk or asterisks (*). For example: 

locate -i*blockchain*use*cases*.


There are tons of other helpful Linux CLI commands, like the pkill command, which is great if you start a shutdown and realize you didn't mean to. But the 10 simple and useful commands described here are the essentials you need to get started using the Linux command line.

Sam Bocetta is a retired defense contractor for the U.S. Navy, a defense analyst, and a freelance journalist. He specializes in finding radical solutions to "impossible"​ ballistics problems. He covers trends in IoT Security, encryption, cryptography, cyberwarfare, and cyberdefense.

14 Comments

How can you miss Ctrl+u from the list of keyboard shortcuts? That's the one I use the most. It's like Ctrl+k but to the other direction (cut from cursor to the beginning of the line).

Touch is not actually for creating files; creating files is a side effect of what it really is and does. `touch file` updates the access time of `file` - which has the side effect of creating `file` as an empty file with zero blocks, if `file` didn't already exist.

me@banshee:/tmp$ touch file ; stat file
File: 'file'
Size: 0 Blocks: 0 IO Block: 4096 regular empty file
Device: 841h/2113d Inode: 692239 Links: 1
Access: (0664/-rw-rw-r--) Uid: ( 1000/ me) Gid: ( 1000/ me)
Access: 2018-04-03 14:34:01.440460376 -0400
Modify: 2018-04-03 14:34:01.440460376 -0400
Change: 2018-04-03 14:34:01.440460376 -0400
Birth: -

me@banshee:/tmp$ touch file ; stat file
File: 'file'
Size: 0 Blocks: 0 IO Block: 4096 regular empty file
Device: 841h/2113d Inode: 692239 Links: 1
Access: (0664/-rw-rw-r--) Uid: ( 1000/ me) Gid: ( 1000/ me)
Access: 2018-04-03 14:34:43.336937192 -0400
Modify: 2018-04-03 14:34:43.336937192 -0400
Change: 2018-04-03 14:34:43.336937192 -0400
Birth: -

* changes access and modification times, sorry.

I think that you named most of the terminal commands that Linux users would agree are fundamental, such as: ls, cd, mv, mkdir, and rm. The command "pwd" is also fundamental if your working directory isn't listed in your prompt.

"rmdir" isn't fundamental for anyone who can use the recursive option with "rm" to delete a directory and its contents, and "touch" isn't fundamental because files can be created using an editor or output redirection. Also, keyboard shortcuts aren't necessary at all and many people will never need the "at" command.

Regarding the "locate" command, if it's considered to be fundamental, then the list of fundamental commands gets a lot longer and "updatedb" becomes an important command.

Off the top of my head, here are some other useful commands for people who want to learn to use the Linux terminal: man, apropos, sudo, su, chown, chmod, find, xargs, grep, sed, mount, less, stat

Everyone's gonna add their own but one of my favorite keyboard shortcuts which works across many flavors of Linux is 'alt-period' which pastes the last word of the previous command. Hitting it repeatedly goes back historically. Amazing how often I use that since I recently learned of it. Anyone know a shortcut to repeat the first element of the previous command?

mv is essentially a renaming command. Yes, there is a rename command, but if you look up its man page, it's a specialized usage of renaming.
mv, of course, doesn't actually move anything, it merely changes the logical location of the file, either just its name, or the entire pathname.

If the source and destination are within the same filesystem then you are correct, nothing gets moved but the pointer to the file. But it will certainly move a file from one partition/filesystem to another if asked to do so.

In reply to by Greg Pittman

You could not be more wrong!

mv of course, does actually move the directory entry for the file from one place to another, and it also copies the file if it needs to, in order to preserve the semantics of moving the directory entry.

In reply to by Greg Pittman

Not a correction - but I think it will improve the document if you provide a full example with rm -r (ex. rm testDir -r) The way it is currently written it implies that it magically figures out the directory name.

man
has got to be in the list of essential commands! Otherwise no one knows what RTFM means! https://xkcd.com/293/

Very Nice. Thanks!

I didn't know all those keyboard shortcuts. Very helpful I love it. Thanks!

Very helpful and relevant article for those less familiar with Linux command line, and also a good refresher for others.
Thank you.

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