How to: Listing all users in a Linux machine

TO list all the users who can access a Linux machine we have to access the /etc/passwd file, which stores information about all registered users of that machine. But it is not really so easy as told above since the file contains many other fields & machine trust accounts & inbuilt accounts.

We'll start by

cat /etc/passwd 

As we all know that by default all the users created will have their home directories in /home share so we'll modify our command a bit by using grep. Now it'll be

cat /etc/passwd | grep "/home"

Now we'll get all the user accounts which have their home share in /home.But the only output we need is the list of users & nothing else. So we'll modify our command again

cat /etc/passwd | grep "/home" |cut -d: -f1

Now what we have done is that we have piped the output of previous command to another variable "cut"

What we have done here is we have added cut -d: -f1
-d: means delimiter :
-f1 means display first field of line i.e. username.

So final command is

cat /etc/passwd | grep "/home" |cut -d: -f1

This works until all your users have their home share in /home. If you have defined their home share to some other destination. Modify the above command accordingly.