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Yves
Asked: 2019-03-08 06:51:48 +0800 CST

Does Ubuntu block the single user mode without password

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Today I try to use the way that I've known for several years to enter the Single User mode: enter the edit mode of grub and add single at the end of line of kernel and type F10.

I thought I could enter the Single User mode without typing password but to my surprise, it asked me to type the root password. I don't know why because I always used this way to rescue my linux system, for example, if I lost the root password, I could use this way to make a new root password.

But now things changed...

So Ubuntu has blocked this non-password single user mode?

password root single-user

1 Answers

  1. Best Answer

    So Ubuntu has blocked this non-password single user mode?

    No. The single user mode does ask a password if there is one set for "root" but that is not the default.

    to type the root password

    Ubuntu does not work with "root" and the password for "root" is set/disabled on installation.

    And then there is systemd. See if ...

    grep ExecStart /usr/lib/systemd/system/rescue.service

    returns a "sulogin" then that is a reason for asking for a password. The parameters in that line will explain what is asked.

    The man page for sulogin explains its behaviour:

    sulogin is invoked by init when the system goes into single-user mode.

The user is prompted:

      Give root password for system maintenance
      (or type Control-D for normal startup):

If the root account is locked and --force is specified, no password is required.
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