7 Linux operators you should know about

Hey devs from all over the world 😊

Okay! I know I am a Frontend developer, but I really like Linux. Just hear me out!

Today, I want to tell you guys about some Linux shell operators that you absolutely can't live without while chaining commands. 🤯

Going forward, we need an example of a command to explain the operators on. Due to our current situation and my absolute hatred, I am using this one :

    kill covid19 --force 

I know it won't work! but, maybe because no one tried it before. 🙄

Let's dive right in, 🌊

Are you after the output?

Starting off, We have the write operator > This one is used to write the output to a file. For example,

    kill covid19 --force > res.txt

Wait a sec! This > will overwrite the content of the file. If you care about res.txt you will have to use the append >> operator which will append the output to the content of the file.

Actually, The output operator > is just a shorthand for 1>

Is there a 2>? Yes!

Is there a 3>? Don't get carried away!✋

1> is for standard program output, while 2> is for error output. For example,

    kill covid19 --force 1> res.txt 2> err.txt

What if your program requires some input file?

I know you guessed it! Just flip it over <

    kill covid19 --force < doctorsList.txt

One command is not enough.

Okay, Let's say it's not that easy. What if we need more? You can chain commands one after the other using the AND operator && like this :

    kill covid19 --force && rebuild

This && is an AND operator. It will only run the next program if the previous one exited successfully.

We also have an OR operator ||

    kill covid19 || (I honestly don't know what to write here! 🤯)

This one will only run the next program if the previous one failed ( Let's hope It doesn't ).

Is that it?

No! We still have more.

Killing covid19 is gonna take some time 😔 We can use the ampersand & at the end to make it run in the background. Leaving the terminal free to run any other programs like this :

    kill covid19 & 

Wait! I am saving the best for last. The most awesome pipe operator | This one can pass the output of one program to the next. Let's try to count the number of lines killing covid19 will output. (cause why not!)

    kill covid19 | wc -l

That's it for now. If you guys liked it, please let me know down in the comments section.

You could also check my Know Your Linux series here on dev.to.

Also, I have a small recommendation -unpaid- for you guys, I have been hacking away my quarantine days and you could too. Check out tryhackme.com. It is super cool!

If you want to know more or if you would like a hacking wingman, hit me up on discord at Bassem Mohamed#3921

As always,
Happy coding 🔥🔥
“كود بسعادة”