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Asked: 2019-01-13 21:15:53 +0800 CST

useradd -g option doesn't seem to be working

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I tried:

sudo useradd -s "/bin/false" -g [existingGroupName] [userNameToAdd]

After the command I looked it up in /etc/group, but the user is not in the [existingGroupName]. Why is that so?

command-line groups useradd

1 Answers

  1. Best Answer

    That's because /etc/group shows the secondary group members (users), not primary ones.

    -g in useradd sets the primary group the user would belong to, which must be only one; whereas -G adds user to single or multiple secondary groups.

    You can check user's primary group (and secondary groups) along with IDs with the id command:

    id <username>

    As a side note, unless intentional, you should use the adduser Perl wrapper of useradd instead of using it directly.

    Another note would be to use getent group instead of directly reading/parsing /etc/group for getting a group info e.g.:

    getent group <group_name>
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