Provided by: dh-sysuser_1.3.1_all 
NAME
dh_sysuser - manage system users, required for package operation
SYNOPSIS
dh_sysuser [debhelper options] [username options] ...
DESCRIPTION
dh_sysuser is debhelper addon, that provide simple and uniform way of creating and removing system users,
required for package operation (for example, to run with dropped privileges).
Process of user creation is delegated to useradd(8) utility, whose behavior is controlled by
/etc/login.defs configuration file. In default installation,
- New user have primary group of same name. It is not be member of any other groups.
- New user have '!' in /etc/shadow password field, making it impossible to login.
- New user have /usr/sbin/nologin as its shell. You still can get new user's shell with su -s.
- If home directory is created (see below), its permissions are affected by UMASK variable in
/etc/login.defs. By default, it results 0755. Files from /etc/skel are NOT copied.
WARNING: Paragraph above means that data, stored in new user's home directory is world-readable. If
you, as package maintainer, need full control over home directory permissions, you are welcome to
file a bug.
dh_sysuser read its arguments from command line and file debian/package.sysuser in pairs, first one being
an username and second one is options.
home
This option request creation of home directory in /var/lib/username. Probably, you should use this
form over explicit one, described below, for uniformity.
home=/path/to/home/directory
This option requests creation of home directory at specified path
defaults
If you do not need any other options, put this one.
CRUFT OF SYSTEM USERS
While it is easy to create system user (and user in general), it is hard to say, when it is safe to
remove it. What should happen to its home directory? What about files outside of home directory? There
was some of discussion (#848239, #848240), and no simple and definitive solution arised. So far, dh-
sysuser do the following on package removal:
- If user have been created without home directory, it is considered safe to remove it.
- If user have been created with home directory, but at time of package removal it is still empty, it
is considered safe to remove both user and his empty home directory.
- If user have been created with home directory, but at time of package removal it is not empty, both
user and its home directory are left alone.
NOTE: As package maintainer, you are encouraged to delete from home directory files, known to be of
little value. It increases chances that home directory will become empty, and user will be removed.
SEE ALSO
useradd(8)