Basic Linux stuff: The passwd file

The passwd file is located at /etc, and in that file is where the username and other user data is stored when a new user is created or when it is modified.
A line that represents the data of a user is written like this:

rukia:x:1000:1000:Rukia:/home/rukia:/bin/bash

1. rukia - Is the username.
2. x - This means that the user has a password. Passwords are encrypted and saved in the shadow file.
3. 1000 - The user ID also known as UID.
4. 1000 - The group ID also known as GID.
5. Rukia - This field is the complete name of the user but it also contains other data. For example, when in Ubuntu we create a new user, it asks for a lot of information like room number, telephone, etc., well all this info is saved in this field and it is known as the gecos field.
6. /home/rukia - The home folder.
7. /bin/bash - Is the shell that will be executed by the user when he or she logins at a terminal.