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acgtyrant
Asked: 2013-02-27 22:24:56 +0800 CST

How to change my UID back in passwd file?

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My OS is Ubuntu 12.10, and my account is called acgtyrant, and its UID is 1000. For the need of researching, I changed my UID from 1000 to 1010 in /etc/passwd, and then I found my files' master changed to a number:1000, which prove my suppose. But when I try to change my UID back, I found I can't edit the passwd file any more! Because when I try to run sudo vim /etc/passwd, the Bash told me sudo: unknown uid 1000: who are you?.

So how to solve it? Acctually I am a chinese student, so forgive my poor English please.

passwd-file

3 Answers

  1. Best Answer

    Press shift during boot then select recovery and drop to a root shell.

    Now mount the file system read-write

    mount -o rw,remount /

    So far you are following the instructions on how to reset your password from here

    Finally don't change your password but simply edit the file 

    vipw

    To edit /etc/passwd or vipw -s to edit /etc/shadow

    Similarly use vigr to edit /etc/group and vigr -s to edit /etc/gshadow

    Standard editors such as nano and vim do not check the file structure before saving so may make problems worse.

    reboot and all should be OK

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  2. Maybe try something like this:

    usermod -u UID_number username
    • 2

  3. two things: have a "backup" user

    already have a root password setup $ sudo passwd root

    login with backup user account, then.

    su

    now as root, nano /etc/passwd change your uid and gid back to original, most likely 1000:1000

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