Redirecting standard error

You will get an error message if you try to display the contents of a file that doesn't exist:

elliot@ubuntu-linux:~$ cat blabla 
cat: blabla: No such file or directory

Now, this error message comes from standard error (stderr). If you try to redirect errors the same way we did with the standard output, it will not work:

elliot@ubuntu-linux:~$ cat blabla > error.txt 
cat: blabla: No such file or directory

As you can see, it still displays the error message on your terminal. That's because stderr is linked to file descriptor 2. And thus, to redirect errors, you have to use 2>:

elliot@ubuntu-linux:~$ cat blabla 2> error.txt

Now if you displayed the contents of the file error.txt, you would see the error message:

elliot@ubuntu-linux:~$ cat error.txt 
cat: blabla: No such file or directory

Let's try to remove a file that doesn't exist:

elliot@ubuntu-linux:~$ rm brrrr
rm: cannot remove 'brrrr': No such file or directory

This also...