RHEL 7.5 - How to remove user from a group?

Question

usermod does not have an option to remove user from a group

Usage: usermod [options] LOGIN

Options:
  -c, --comment COMMENT         new value of the GECOS field
  -d, --home HOME_DIR           new home directory for the user account
  -e, --expiredate EXPIRE_DATE  set account expiration date to EXPIRE_DATE
  -f, --inactive INACTIVE       set password inactive after expiration
                                to INACTIVE
  -g, --gid GROUP               force use GROUP as new primary group
  -G, --groups GROUPS           new list of supplementary GROUPS
  -a, --append                  append the user to the supplemental GROUPS
                                mentioned by the -G option without removing
                                him/her from other groups
  -h, --help                    display this help message and exit
  -l, --login NEW_LOGIN         new value of the login name
  -L, --lock                    lock the user account
  -m, --move-home               move contents of the home directory to the
                                new location (use only with -d)
  -o, --non-unique              allow using duplicate (non-unique) UID
  -p, --password PASSWORD       use encrypted password for the new password
  -R, --root CHROOT_DIR         directory to chroot into
  -s, --shell SHELL             new login shell for the user account
  -u, --uid UID                 new UID for the user account
  -U, --unlock                  unlock the user account
  -Z, --selinux-user SEUSER     new SELinux user mapping for the user account

Which command & options are used to remove a user from a group?

Solution

The appropriate option is -G, but you don’t specify groups you want to remove, you specify groups you want to keep. If user is a member of group1 and group2, you can remove group2 by running

usermod -G group1 user

This will update user so that the only supplementary group membership is group1.

As mentioned in How do I remove a user from a group?, you can also use gpasswd:

gpasswd -d user group2

will remove user from group2.

Comments

[Admin]

Possible duplicate unix.stackexchange.com/questions/29570/…

[Admin]

@Panther Reviewed and used all the options used in that query. no luck

[Admin]

@Panther I tried usermod -G wheel appuser, it did not remove appuser from wheel