User Group Perms Through Terminal

[brken11]

Is it possible to edit group permissions through terminal?

Because my main account, has gone weird,

-there is no background
-some of my launchers are missing
-the window borders are missing so I con only move window that you can move through the center
-I can't access eclipse for some reason

But my two other accounts, my sisters and my guest account still work
but they don't have permissions to create and delete accounts.
The reason I don't have any pics to show you is because I can't get to the screenshot application.

So is there a way I can use terminal on my messed up account to change a permission?
I need to recreate my account but I need a different user to do it for me but that user doesn't have the permissions.
That's why I need a way to edit the permissions of my sisters account.

[DrHu]

https://en.wikipedia.org/wiki/Chgrp

chgrp/chown command line
http://www.mediacollege.com/linux/command/chgrp.html
http://www.mediacollege.com/linux/command/chown.html

Also groups or users to check which group or user you or the user you are checking belongs to.
--your first user account is an admin/sudo and belongs to either the admin group or the sudo group (in later version of the Linux OS, released by Mint

If the sudo command won't work for you, you can try su
https://en.wikipedia.org/wiki/Su_(Unix)

[brken11]

See the thing I need is to be able to create another admin user.
That way I can move all my data to the new account and delete the messed-up old on.

[brken11]

A command to launch system settings would also work.

[austin.texas]

Do you have a /home partition which is shared by other users?

Please enter the command groups in a terminal and post the result here.

A command to launch system settings would also work.

You have not mentioned which desktop you are using, or which version of Mint.