Normally, you won’t log out until you have finished using the UNIX® system. However, we cover it here as it logically pairs up with the subject of logging in.
Why the need to ‘log out’?
As we’ve already said, the reason for logging in in the first place is to identify you to the system, so it knows which files and areas to give you access to. It allows you access to the areas you are supposed to have access to, and blocks users from each others’ areas.
Logging out is the opposite – you are telling the system that you have finished using it for the time being, and that you no longer require access to your files at this time. It is very important that you log out when you have finished using the system, and preferably every time you leave your computer or terminal unattended. If you leave yourself logged in, then someone else may wander up to the terminal you have been using, and have access to all your files. They may read, modify, or delete them. They may send emails out from your user ID. They may even attempt to hack or damage the system from your user ID and this is your responsibility. By logging out, you prevent anyone else from using your user ID.
There are several ways to log out. They all achieve the same thing – you will understand the difference between then later on, but for now you must simply make sure that you do log out every time you finish with the system.
The best way is to use the command ‘logout’ and any prompt. For example:
The system will usually give you some sort of ‘farewell’ message, and then will return to the login screen to allow someone else to log in. Your exact ‘farewell’ message varies, and you may or may not get a message at all. For example:
Thank you for using london-pro – you are now logging out.
Here you can see that the user has been logged out, and after a brief message, the system is prompting the next login request. At this stage, you may not access any of your files or programs – you are no longer logged into the system.
We said there were several ways to log out. We just saw the ‘logout’ command. Two other ways to log out are (1) – to use the ‘exit’ command, and (2) – to press ‘CTRL-D’. These both amount to the same thing. For now, the main point is to remember to log out when you are finished – leaving yourself logged in is the number one mistake to be avoided!