Wednesday, December 28, 2016

Linux Command Line Tutorial For Beginners 23 - userdel command (Removing...



USERDEL(8)                                   System Management Commands                                   USERDEL(8)



NAME
       userdel - delete a user account and related files

SYNOPSIS
       userdel [options] LOGIN

DESCRIPTION
       userdel is a low level utility for removing users. On Debian, administrators should usually use deluser(8)
       instead.

       The userdel command modifies the system account files, deleting all entries that refer to the user name
       LOGIN. The named user must exist.

OPTIONS
       The options which apply to the userdel command are:

       -f, --force
           This option forces the removal of the user account, even if the user is still logged in. It also forces
           userdel to remove the user's home directory and mail spool, even if another user uses the same home
           directory or if the mail spool is not owned by the specified user. If USERGROUPS_ENAB is defined to yes
           in /etc/login.defs and if a group exists with the same name as the deleted user, then this group will be
           removed, even if it is still the primary group of another user.

           Note: This option is dangerous and may leave your system in an inconsistent state.

       -h, --help
           Display help message and exit.

       -r, --remove
           Files in the user's home directory will be removed along with the home directory itself and the user's
           mail spool. Files located in other file systems will have to be searched for and deleted manually.

           The mail spool is defined by the MAIL_DIR variable in the login.defs file.

       -R, --root CHROOT_DIR
           Apply changes in the CHROOT_DIR directory and use the configuration files from the CHROOT_DIR directory.

       -Z, --selinux-user
           Remove any SELinux user mapping for the user's login.

CONFIGURATION
       The following configuration variables in /etc/login.defs change the behavior of this tool:

       MAIL_DIR (string)
           The mail spool directory. This is needed to manipulate the mailbox when its corresponding user account is
           modified or deleted. If not specified, a compile-time default is used.

       MAIL_FILE (string)
           Defines the location of the users mail spool files relatively to their home directory.

       The MAIL_DIR and MAIL_FILE variables are used by useradd, usermod, and userdel to create, move, or delete the
       user's mail spool.

       MAX_MEMBERS_PER_GROUP (number)
           Maximum members per group entry. When the maximum is reached, a new group entry (line) is started in
           /etc/group (with the same name, same password, and same GID).

           The default value is 0, meaning that there are no limits in the number of members in a group.

           This feature (split group) permits to limit the length of lines in the group file. This is useful to make
           sure that lines for NIS groups are not larger than 1024 characters.

           If you need to enforce such limit, you can use 25.

           Note: split groups may not be supported by all tools (even in the Shadow toolsuite). You should not use
           this variable unless you really need it.

       USERDEL_CMD (string)
           If defined, this command is run when removing a user. It should remove any at/cron/print jobs etc. owned
           by the user to be removed (passed as the first argument).

           The return code of the script is not taken into account.

           Here is an example script, which removes the user's cron, at and print jobs:

               #! /bin/sh

               # Check for the required argument.
               if [ $# != 1 ]; then
                    echo "Usage: $0 username"
                    exit 1
               fi

               # Remove cron jobs.
               crontab -r -u $1

               # Remove at jobs.
               # Note that it will remove any jobs owned by the same UID,
               # even if it was shared by a different username.
               AT_SPOOL_DIR=/var/spool/cron/atjobs
               find $AT_SPOOL_DIR -name "[^.]*" -type f -user $1 -delete \;

               # Remove print jobs.
               lprm $1

               # All done.
               exit 0



       USERGROUPS_ENAB (boolean)
           If set to yes, userdel will remove the user's group if it contains no more members, and useradd will
           create by default a group with the name of the user.

FILES
       /etc/group
           Group account information.

       /etc/login.defs
           Shadow password suite configuration.

       /etc/passwd
           User account information.

       /etc/shadow
           Secure user account information.

EXIT VALUES
       The userdel command exits with the following values:

       0
           success

       1
           can't update password file

       2
           invalid command syntax

       6
           specified user doesn't exist

       8
           user currently logged in

       10
           can't update group file

       12
           can't remove home directory

CAVEATS
       userdel will not allow you to remove an account if there are running processes which belong to this account.
       In that case, you may have to kill those processes or lock the user's password or account and remove the
       account later. The -f option can force the deletion of this account.

       You should manually check all file systems to ensure that no files remain owned by this user.

       You may not remove any NIS attributes on a NIS client. This must be performed on the NIS server.

       If USERGROUPS_ENAB is defined to yes in /etc/login.defs, userdel will delete the group with the same name as
       the user. To avoid inconsistencies in the passwd and group databases, userdel will check that this group is
       not used as a primary group for another user, and will just warn without deleting the group otherwise. The -f
       option can force the deletion of this group.

SEE ALSO
       chfn(1), chsh(1), passwd(1), login.defs(5), gpasswd(8), groupadd(8), groupdel(8), groupmod(8), useradd(8),
       usermod(8).



shadow-utils 4.1.5.1                                 02/17/2014                                           USERDEL(8)