Provided by:
passwd_4.0.18.2-1ubuntu2_i386 
NAME
userdel - delete a user account and related files
SYNOPSIS
userdel [options] LOGIN
DESCRIPTION
userdel is a low level utility for adding 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.
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 the user is
currently logged in. You must kill any running processes which belong
to an account that you are deleting.
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 user 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).