bash - Can you delete all users but specified accounts in Ubuntu?

07
2014-07

Dylan

I am trying to find a way to quickly delete all user accounts except for the ones I specify in Ubuntu. Is there a good way of doing this? Perhaps a bash script that could do this function? I searched around and didn't really see anything.

I am doing this as a way to harden a system I am getting ready to take control over so I can remove all of the users except the ones I specify. There are several users.

Answers

John1024

Put the names of the accounts that you want to keep, one name per line, in the file keepers and run:

cut -d: -f1 /etc/passwd | grep -vFf keepers | while read name ; do deluser "$name" ; done

The above uses cut to get all the current user names from /etc/passwd. The command grep -vFf keepers removes from that list all names except the ones in listed keepers. Note that there are many system users that you will need to keep such as root, daemon, sys, mail, lp, etc. The do while loop deletes each name.

deluser has many options. See man deluser.

You might want to backup up your /etc/passwd, /etc/group, and other files before doing this just to be safe.

For the cautious, a two step approach

The first step creates a file with list of all accounts to be removed:

cut -d: -f1 /etc/passwd | grep -vFf keepers >goners

The file goners should be carefully inspected to assure that no important accounts are in it. It may be edited by hand if desired. Then run:

while read name ; do deluser "$name" ; done <goners

Related Answers

MDMarra

I'm off the network and want to learn all that I can

If you really want to learn all that you can, you should be doing things the proper way. Lesson 1 is never log in as root directly. Lesson two is how to use the terminal. If you're not willing to learn how to use the terminal then maybe WAMP is more appropriate for you than LAMP. Linux is a very powerful operating system, but it is not Windows and trying to treat it as such is dangerous.

Pascal Thivent

Use sudo (or gskudo for graphical applications) to run commands with super user privileges (at your own risks).

(EDIT: As people mentioned in comments, it's not possible by default to login as root as root doesn't have a password, which is a good thing, and I'm not going to tell you how to change this as I consider setting a password for root as a huge security flaw and a very bad practice. There is actually no reason to be permanently logged a root, this can only lead to mistakes and disasters. Just DON'T DO IT.)

mac

As already reiterated to the boredom, staying logged as superuser all the time is a very bad idea. That said, it's your computer, your project, your choice, so I don't see why one should not share the information you asked, so...

sudo passwd root

this will allow you to enter a password for your root user. You can now logout and login again using your root user.

Should you change your idea about using root, then you could still implement a drag&drop mechanism for super-user operations. Have a look to the ubuntu wiki!

8088

Why don't you just Alt + F2 and type:

gksudo nautilus

Enter your password once and use nautilus as a superuser - don't close it. You can also use Ctrl + T or Ctrl + N to open tabs or new windows without re-entering your password.

mathepic

There is a reason Ubuntu disables this and gives you "sudo" instead.

Doing this is a compromise to your system, and being lazy is not enough reason.

Oliver Ridgway

Despite all the judging comments here I think people should be able to decide for themselves.

The ubuntu wiki explains how to access the root account, and alternatives.

https://help.ubuntu.com/community/RootSudo

Home

bash - Can you delete all users but specified accounts in Ubuntu?

For the cautious, a two step approach