debian-debian-adduser/doc/adduser.8

.\" Copyright: 1994 Ian A. Murdock <imurdock@debian.org>
.\"            1995 Ted Hajek <tedhajek@boombox.micro.umn.edu>
.\"            1997-1999 Guy Maor
.\"            2000-2003 Roland Bauerschmidt <rb@debian.org>
.\"            2004-2025 Marc Haber <mh+debian-packages@zugschlus.de
.\"            2005-2009 Jörg Hoh <joerg@joerghoh.de
.\"            2006-2011 Stephen Gran <sgran@debian.org>
.\"            2011 Justin B Rye <jbr@edlug.org.uk>
.\"            2016 Afif Elghraoui <afif@debian.org>
.\"            2016 Helge Kreutzmann <debian@helgefjell.de>
.\"            2021-2022 Jason Franklin <jason@oneway.dev>
.\"            2022 Matt Barry <matt@hazelmollusc.org>
.
.\" This is free software; see the GNU General Public License version
.\" 2 or later for copying conditions.  There is NO warranty.
.TH ADDUSER 8 "" "Debian GNU/Linux"
.SH NAME
adduser, addgroup \- add or manipulate users or groups
.SH SYNOPSIS
.SY adduser
.OP \-\-add\-authorized\-key key
.OP \-\-add\-extra\-groups
.OP \-\-allow\-all\-names
.OP \-\-allow\-bad\-names
.OP \-\-comment comment
.OP \-\-conf file
.OP \-\-debug
.OP \-\-disabled\-login
.OP \-\-disabled\-password
.OP \-\-encrypt\-home
.OP \-\-firstgid id
.OP \-\-firstuid id
.OP \-\-force-home
.OP \-\-gid id
.OP \-\-home dir
.OP \-\-ingroup group
.OP \-\-lastgid id
.OP \-\-lastuid id
.OP \-\-no\-create\-home
.OP \-\-no\-copy\-skel
.OP \-\-shell shell
.OP \-\-quiet
.OP \-\-uid id
.OP \-\-verbose
.OP \-\-stdoutmsglevel prio
.OP \-\-stderrmsglevel prio
.OP \-\-logmsglevel prio
.B user
.YS
.SY adduser
.B \-\-system
.OP \-\-comment comment
.OP \-\-conf file
.OP \-\-debug
.OP \-\-gid id
.OP \-\-group
.OP \-\-home dir
.OP \-\-ingroup group
.OP \-\-no\-create\-home
.OP \-\-no\-copy\-skel
.OP \-\-shell shell
.OP \-\-uid id
.OP \-\-quiet
.OP \-\-verbose
.OP \-\-stdoutmsglevel prio
.OP \-\-stderrmsglevel prio
.OP \-\-logmsglevel prio
.B user
.YS
.SY adduser
.B \-\-unlock
.OP \-\-system
.B user
.YS
.SY adduser
.B \-\-group
.OP \-\-conf file
.OP \-\-debug
.OP \-\-firstgid id
.OP \-\-gid ID
.OP \-\-lastgid id
.OP \-\-quiet
.OP \-\-verbose
.OP \-\-stdoutmsglevel prio
.OP \-\-stderrmsglevel prio
.OP \-\-logmsglevel prio
.B group
.YS
.SY addgroup
.OP \-\-conf file
.OP \-\-debug
.OP \-\-firstgid id
.OP \-\-gid ID
.OP \-\-lastgid id
.OP \-\-quiet
.OP \-\-verbose
.OP \-\-stdoutmsglevel prio
.OP \-\-stderrmsglevel prio
.OP \-\-logmsglevel prio
.B group
.YS
.SY addgroup
.B \-\-system
.OP \-\-gid id
.OP \-\-conf file
.OP \-\-quiet
.OP \-\-verbose
.OP \-\-stdoutmsglevel prio
.OP \-\-stderrmsglevel prio
.OP \-\-logmsglevel prio
.B group
.YS
.SY adduser
.OP \-\-conf file
.OP \-\-debug
.OP \-\-quiet
.OP \-\-verbose
.OP \-\-stdoutmsglevel prio
.OP \-\-stderrmsglevel prio
.OP \-\-logmsglevel prio
.B user
.B group
.YS
.SY adduser
.B \-\-help
.YS
.SY adduser
.B \-\-version
.YS
.SH DESCRIPTION
\fBadduser\fP and \fBaddgroup\fP add users and groups to the system
according to command line options
and configuration information in \fI/etc/adduser.conf\fP.
They are more Debian specific front ends to the
\fBuseradd\fP, \fBgroupadd\fP and \fBusermod\fP programs,
which are more distribution agnostic.
\fBadduser\fP and \fBaddgroup\fP
by default choose Debian policy conformant UID and GID values,
create a home directory with skeletal configuration,
run a custom script,
and have other features.
.PP
\fBadduser\fP and \fBaddgroup\fP are intended as a policy layer,
making it easier for package maintainers and local administrators
to create local system accounts
in the way Debian expects them to be created,
taking the burden to adapt to the probably changing specifications
of Debian policy.
\fBadduser \-\-system\fP takes special attention
on just needing a single call in the package maintainer scripts
without any conditional wrappers,
error suppression or other scaffolding.
.PP
\fBadduser\fP honors the distinction between
\fIdynamically allocated system users and groups\fP
and
\fIdynamically allocated user accounts\fP
that is documented in Debian Policy, Chapter 9.2.2.
.PP
For a full list and explanations of all options,
see the OPTIONS section.
.PP
\fBadduser\fP and \fBaddgroup\fP can be run in one of five modes:
.SS "Add a regular (non-system) user"
If called with one non-option argument and
without the \fB\-\-system\fP or \fB\-\-group\fP options,
\fBadduser\fP will add a regular user,
that means a
\fIdynamically allocated user account\fP
in the sense of Debian Policy.
This is commonly referred to in \fBadduser\fP as a \fInon-system user.\fP
.PP
If \fBadduser\fP is called with the \fB\-\-unlock\fP option, it will
search for an existing account, and ensure it is unlocked.
If the user is not found, \fBadduser\fP will return an error.
See \fBUnlock an account\fP below for more details.
.PP
\fBadduser\fP will choose the first available UID
from the range specified by
\fBFIRST_UID\fP and \fBLAST_UID\fP
in the configuration file.
The range may be overridden with the
\fB\-\-firstuid\fP and \fB\-\-lastuid\fP options.
Finally, the UID can be set fully manually with the \fB\-\-uid\fP option.
.PP
By default, each user is given a corresponding group with the same name
and the same numeric ID as the user,
unless \fB\-\-ingroup\fP is used (see below).
This is commonly called
\fIUsergroups\fP
and allows group writable directories to be easily maintained
by placing the appropriate users in the new group,
setting the set-group-ID bit in the directory,
and ensuring that all users use a umask of 002.
.PP
For this usergroup case,
\fBadduser\fP does not pick a UID and a GID independently.
Instead, it searches for the first number that is simultaneously
available as a UID and as a GID,
and assigns that single number to both the new user and the new group.
The range searched is the
.I intersection
of the UID range
(\fBFIRST_UID\fP to \fBLAST_UID\fP,
or \fB\-\-firstuid\fP / \fB\-\-lastuid\fP if given)
and the GID range
(\fBFIRST_GID\fP to \fBLAST_GID\fP,
or \fB\-\-firstgid\fP / \fB\-\-lastgid\fP if given):
that is, the search starts at the higher of the two range minimums
and ends at the lower of the two range maximums.
If the configured UID and GID ranges do not overlap at all,
or no number free in both ranges can be found,
\fBadduser\fP fails outright;
it does not fall back to assigning the user and group different numbers.
.PP
If \fB\-\-ingroup\fP is given
to add the new user to an already existing group
instead of a new usergroup,
this combined search does not apply.
Instead,
if the requested group's GID happens to also be free as a UID
within the configured UID range,
\fBadduser\fP prefers that number for the new user's UID,
so the user still ends up with a UID matching the group's GID
even though the group was not newly created as a usergroup.
If the GID is not free as a UID,
or falls outside the UID range,
\fBadduser\fP falls back to choosing
the first available UID from the UID range,
as it always did.
.PP
Finally, the UID and/or GID can each be set fully manually
with the \fB\-\-uid\fP and \fB\-\-gid\fP options,
which bypass the search(es) above for the value(s) given.
.PP
The interaction between
\fBUSERS_GID\fP, \fBUSERS_GROUP\fP, and \fBUSERGROUPS\fP
is explained in detail in
.BR adduser.conf (5).
.PP
The new user's primary group can also be overridden
from the command line
with the \fB\-\-gid\fP or \fB\-\-ingroup\fP options
to set the group by id or name,
respectively.
Also,
users can be added
to one or more supplemental groups
defined as \fBEXTRA_GROUPS\fP
either by setting \fBADD_EXTRA_GROUPS\fP to 1
in the configuration file,
or by passing \fB\-\-add\-extra\-groups\fP on the command line.
.PP
\fBadduser\fP will copy files from \fI/etc/skel\fP
into the home directory and
prompt for the comment field and a password
if those functions have not been turned off / overridden
from the command line.
.PP
UID, comment, home directory and shell
might be pre-determined with the \fBUID_POOL\fP and \fBGID_POOL\fP option,
documented in
.BR adduser.conf (5).

To set up an encrypted home directory for the new user, add the
.B \-\-encrypt\-home
option.
For more information, refer to the \-b option of
.BR ecryptfs-setup-private (1).

.SS "Add a system user"
If called with one non-option argument and the \fB\-\-system\fP option,
\fBadduser\fP will add a
\fIdynamically allocated system user,\fP
often abbreviated as
\fIsystem user\fP
in the context of the \fBadduser\fP package.
.PP
If the user already exists and is a system account, then
\fBadduser\fP will ensure the account is unlocked and return
successfully.
See \fBUnlock a user account\fP below.
.PP
\fBadduser\fP will choose the first available UID
from the range specified by
\fBFIRST_SYSTEM_UID\fP and \fBLAST_SYSTEM_UID\fP
in the configuration file.
This can be overridden with the \fB\-\-uid\fP option.
.PP
By default, system users are assigned \fBnogroup\fP as primary group.
To assign an already existing group as primary group,
use the \fB\-\-gid\fP or \fB\-\-ingroup\fP options.
.PP
If the \fB\-\-group\fP option is given
and the identically named group does not already exist,
it is created with the same numeric ID as the user,
following the same logic as for a non-system usergroup
(see \fBAdd a regular (non-system) user\fP above):
\fBadduser\fP searches for the first number that is simultaneously
available as a UID and as a GID,
within the intersection of the UID range
(\fBFIRST_SYSTEM_UID\fP to \fBLAST_SYSTEM_UID\fP,
or \fB\-\-firstuid\fP / \fB\-\-lastuid\fP if given)
and the GID range
(\fBFIRST_SYSTEM_GID\fP to \fBLAST_SYSTEM_GID\fP,
or \fB\-\-firstgid\fP / \fB\-\-lastgid\fP if given).
As with a regular usergroup,
if the configured UID and GID ranges do not overlap at all,
or no number free in both ranges can be found,
\fBadduser\fP fails outright
rather than assigning the user and group different numbers.
.PP
If instead \fB\-\-gid\fP or \fB\-\-ingroup\fP is used
to assign an already existing group as primary group,
this combined search does not apply.
Instead,
if that group's GID happens to also be free as a UID
within the configured UID range,
\fBadduser\fP prefers that number for the new system user's UID.
Note that for a non-system user (see above),
only \fB\-\-ingroup\fP triggers this preference;
\fB\-\-gid\fP alone does not.
If the GID is not free as a UID,
or falls outside the UID range,
\fBadduser\fP falls back to choosing
the first available UID from the UID range,
as it always did.
.PP
If no home directory is specified,
the default home directory for a new system user
is \fI\%/nonexistent\fP.
This directory should never exist on any Debian system,
and \fBadduser\fP will never create it automatically.
.PP
If a home directory is specified with the \fB\-\-home\fP option,
and the directory does already exist
(for example, if the package ships with files in that directory),
\fBadduser\fP silently does not set the owner of the directory
to the newly created user.
Setting the owner might override a decision of the local admin,
and reporting the fact would break \fBadduser\fP's silence
during package installation.
If you use \fBadduser \-\-home\fP in your package's maintainer scripts,
you might want to issue an explicit recursive \fBchown\fP for the
home directory after the call to \fBadduser\fP.
.PP
Unless a shell is explicitly set with the \fB\-\-shell\fP option,
the new system user will have the shell set to
\fI/usr/sbin/nologin\fP.
\fBadduser \-\-system\fP does not set a password for the new account.
It is an error if \fBadduser \-\-system\fP is called
for an account that has a password.
Skeletal configuration files are not copied.
.PP
Other options will behave as for the creation of a regular user.
The files referenced by \fBUID_POOL\fP and \fBGID_POOL\fP are also honored.

.SS "Unlock a user account"
If called with the \fB\-\-unlock\fP option, \fBadduser\fP will
unlock an existing, previously locked account.
If found, the user's password will be re-enabled,
and expiry restrictions will be removed.
Any previous expiry settings will have to be
added manually after unlocking the account.

.SS "Add a group"
If \fBadduser\fP is called with the \fB\-\-group\fP option and
without the \fB\-\-system\fP option, or
\fBaddgroup\fP is called respectively,
a user group will be added.
.PP
A
\fIdynamically allocated system group,\fP
often abbreviated as \fIsystem group\fP
in the context of the \fBadduser\fP package,
will be created
if \fBadduser \-\-group\fP or \fBaddgroup\fP
are called with the \fB\-\-system\fP option.
.PP
A GID will be chosen from the respective range specified for GIDs
in the configuration file
(\fBFIRST_GID\fP, \fBLAST_GID\fP,
\fBFIRST_SYSTEM_GID\fP, \fBLAST_SYSTEM_GID\fP).
To override that mechanism,
you can give the GID using the \fB\-\-gid\fP option.
.PP
For non-system groups,
the range specified in the configuration file may be overridden
with the \fB\-\-firstgid\fP and \fB\-\-lastgid\fP options.
.PP
The group is created with no members.

.SS "Add an existing user to an existing group"
If called with two non-option arguments,
\fBadduser\fP will add an existing user to an existing group.

.SH OPTIONS
Different modes of \fBadduser\fP allow different options.
If no valid modes are listed for a option,
it is accepted in all modes.
.PP
Short versions for certain options may exist for historical reasons.
They are going to stay supported, but are removed from the documentation.
Users are advised to migrate to the long version of options.
.TP
.B \-\-add\-authorized\-key key
Add
.I key
to the \fI\%~/.ssh/authorized_keys\fP file of the new user.
If
.I key
is the name of an existing file,
the contents of that file are added,
which allows to add several keys at once.
Otherwise,
.I key
is taken literally as a single key.
The option can be given more than once.
Keys are appended to \fI\%authorized_keys\fP,
so that keys shipped in \fI\%/etc/skel\fP are kept.
Keys are not checked for validity;
an unusable key is going to be rejected by the SSH daemon later.
No key is installed if the home directory has not been created by
\fB\%adduser\fP,
for example if \fB\-\-no\-create\-home\fP has been given,
if the home directory is \fI\%/nonexistent\fP,
or if the home directory does already exist.
In that case,
a warning is issued and the user is still created.
Note that \fB\%sshd\fP with \fBStrictModes\fP enabled ignores
\fI\%authorized_keys\fP if the home directory or \fI\%~/.ssh\fP
is writable by group or other,
which can happen with a permissive \fBDIR_MODE\fP setting.
Valid modes: \fBadduser\fP.
.TP
.B \-\-add\-extra\-groups
Add new user to extra groups defined in the configuration files'
\fBEXTRA_GROUPS\fP setting.
The old spelling \fB\-\-add_extra_groups\fP is deprecated and
will be supported in Debian bookworm only.
Valid modes: \fBadduser\fP, \fBadduser \-\-system\fP.
.TP
.B \-\-allow\-all\-names
Allow any user- and groupname which is supported by the underlying
\fBuseradd\fP(8).
See VALID NAMES below.
Valid modes: \fBadduser\fP, \fBadduser \-\-system\fP,
\fBaddgroup\fP, \fBaddgroup \-\-system\fP.
.TP
.B \-\-allow\-bad\-names
Disable \fBNAME_REGEX\fP and \fBSYS_NAME_REGEX\fP check of names.
Only a weaker check for validity of the name is applied.
See VALID NAMES below.
Valid modes: \fBadduser\fP, \fBadduser \-\-system\fP,
\fBaddgroup\fP, \fBaddgroup \-\-system\fP.
.TP
.BI \-\-comment " comment"
Set the comment field for the new entry generated.
\fBadduser\fP will not ask for the information if this option is given.
This field is also known under the name GECOS field
and contains information that is used by the \fBfinger\fR(1) command.
This used to be the \fB\-\-gecos\fR option,
which is deprecated and will be removed after Debian bookworm.
Valid modes: \fBadduser\fP, \fBadduser \-\-system\fP.
.TP
.BI \-\-conf " file"
Use \fIfile\fP instead of \fI/etc/adduser.conf\fP.
Multiple \fB\-\-conf\fR options can be given.
.TP
.B \-\-debug
Synonymous to
.BR \-\-stdoutmsglevel=debug .
Deprecated.
.TP
.B \-\-disabled\-login
.TQ
.B \-\-disabled\-password
Do not run \fBpasswd\fP(1) to set a password.
In most situations, logins are still possible though
(for example using SSH keys or through PAM)
for reasons that are beyond \fBadduser\fP's scope.
\fB\-\-disabled\-login\fP will additionally set the shell to
\fI/usr/sbin/nologin\fP.
Valid mode: \fBadduser\fP.
.TP
.BI \-\-firstuid " ID"
.TQ
.BI \-\-lastuid " ID"
.TQ
.BI \-\-firstgid " ID"
.TQ
.BI \-\-lastgid " ID"
Override the first UID / last UID / first GID / last GID
in the range that the uid is chosen from
(\fBFIRST_UID\fP, \fBLAST_UID\fP, \fBFIRST_GID\fP and \fBLAST_GID\fP,
\fBFIRST_SYSTEM_UID\fP, \fBLAST_SYSTEM_UID\fP,
\fBFIRST_SYSTEM_GID\fP and \fBLAST_SYSTEM_GID\fP
in the configuration file).
If a group is created as a usergroup
(that is, for \fBadduser\fP without \fB\-\-ingroup\fP,
or for \fBadduser \-\-system \-\-group\fP without \fB\-\-ingroup\fP),
\fB\-\-firstgid\fP and \fB\-\-lastgid\fP are
.B not
ignored:
they bound the GID side of the combined UID/GID search
described under
\fBAdd a regular (non-system) user\fP
above,
so a narrower or shifted \fB\-\-firstgid\fP\^/\fB\-\-lastgid\fP\^
range can change which number is chosen,
or cause the search to fail
if it no longer overlaps the UID range at all.
The resulting group always gets the same numeric ID as the user.
If \fB\-\-ingroup\fP is used instead,
\fB\-\-firstgid\fP and \fB\-\-lastgid\fP have no effect;
\fB\-\-firstuid\fP and \fB\-\-lastuid\fP still bound
whether the requested group's GID
can be preferred as the new user's UID
(see \fBAdd a regular (non-system) user\fP above).
Valid modes: \fBadduser\fP, \fBadduser \-\-system\fP,
for \fP\-\-firstgid\fP and \fB\-\-lastgid\fR also
\fBaddgroup\fP.
.TP
.B \-\-force\-badname
.TQ
.B \-\-allow\-badname
These are the deprecated forms of \fB\-\-allow\-bad\-names\fR.
They will be removed
during the release cycle of Debian 13.
.TP
.BI \-\-gid " GID"
When creating a group,
this option sets the group ID number of the new group to \fIGID\fP.
When creating a user,
this option sets the primary group ID number of the new user
to \fIGID\fP.
For \fBadduser \-\-system\fP specifically,
if the chosen UID is not also given explicitly with \fB\-\-uid\fP,
and \fIGID\fP happens to also be free as a UID
within the UID range in effect,
\fBadduser\fP prefers that number for the new user's UID
(see \fB\-\-ingroup\fP).
This does not apply to a non-system \fBadduser\fP:
there, \fB\-\-gid\fP alone never influences UID selection this way.
Valid modes: \fBadduser\fP, \fBadduser \-\-system\fP,
\fBaddgroup\fP, \fBaddgroup \-\-system\fP.
.TP
.B \-\-group
Using this option in \fBadduser \-\-system\fP
indicates that the new user should get
an identically named group as its primary group.
If that identically named group is not already present, it is created.
If not combined with \fB\-\-system\fP,
a group with the given name is created.
The latter is the default action if
the program is invoked as \fBaddgroup\fP.
Valid modes: \fBadduser \-\-system\fP,
\fBaddgroup\fP, \fBaddgroup \-\-system\fP.
.TP
.B \-\-help
Display brief instructions.
.TP
.BI \-\-home " dir"
Use \fIdir\fP as the user's home directory,
rather than the default specified by the configuration file
(or \fI/nonexistent\fP if \fBadduser \-\-system\fP is used).
If the directory does not exist, it is created.
Valid modes: \fBadduser\fP, \fBadduser \-\-system\fP.
.TP
.BI \-\-ingroup " GROUP"
When creating a user,
this option sets the primary group ID number of the new user
to the GID of the named group.
Unlike with the \fB\-\-gid\fP option,
the group is specified here by name rather than by numeric ID number.
The group must already exist.
If the chosen UID is not also given explicitly with \fB\-\-uid\fP,
and \fIGROUP\fP's GID happens to also be free as a UID
within the UID range in effect
(see \fB\-\-firstuid\fP / \fB\-\-lastuid\fP),
\fBadduser\fP prefers that number for the new user's UID,
so the user ends up with a UID matching the group's GID
even though the group itself was not newly created.
Otherwise, the first available UID in range is used, as before.
Valid modes: \fBadduser\fP, \fBadduser \-\-system\fP.
.TP
.BI \-\-lastuid " ID"
.TQ
.BI \-\-lastgid " ID"
Override the last UID / last GID.
See \fB\-\-firstuid\fP.
.TP
.B \-\-no\-create\-home
Do not create a home directory for the new user.
Note that the pathname for the new user's home directory
will still be entered in the appropriate field
in the \fI\%/etc/passwd\fP file.
The use of this option does not imply that this field should be empty.
Rather, it indicates to \fB\%adduser\fP
that some other mechanism will be responsible
for initializing the new user's home directory.
Valid modes: \fBadduser\fP, \fBadduser \-\-system\fP.
.TP
.B \-\-force\-home
Assume the home directory does already exist
and has been taken care of by the local administrator.
\fIchown\fP the directory to the newly created user and
populate it with the files from \fI\%/etc/skel\fP
without double checking.
This allows to put new home directories on an
md, lvm, or dm-crypt device.
Valid modes: \fBadduser\fP.
.TP
.B \-\-no\-copy\-skel
Do not populate the home directory for the new user with
files from \fI\%/etc/skel\fP.
If the home directory is newly created, it will be empty.
Valid modes: \fBadduser\fP, \fBadduser \-\-system\fP.
.TP
.B \-\-quiet
Synonymous to
.BR \-\-stdoutmsglevel=warn .
Deprecated.
.TP
.BI \-\-shell " shell"
Use \fIshell\fP as the user's login shell,
rather than the default specified by the configuration file
(or \fI/usr/sbin/nologin\fP if \fBadduser \-\-system\fP is used).
Valid modes: \fBadduser\fP, \fBadduser \-\-system\fP.
.TP
.B \-\-system
Normally, \fBadduser\fP creates
\fIdynamically allocated user accounts and groups\fP
as defined in Debian Policy, Chapter 9.2.2.
With this option, \fBadduser\fP creates a
\fIdynamically allocated system user and group\fP
and changes its mode respectively.
Valid modes: \fBadduser\fP, \fBaddgroup\fP.
.TP
.BI \-\-uid " ID"
Force the new userid to be the given number.
\fBadduser\fP will fail if the userid is already taken.
Valid modes: \fBadduser\fP, \fBadduser \-\-system\fP.
.TP
.B \-\-verbose
Synonymous to
.BR \-\-stdoutmsglevel=info .
Deprecated.
.TP
.BI \-\-stdoutmsglevel " prio"
.TQ
.BI \-\-stderrmsglevel " prio"
.TQ
.BI \-\-logmsglevel " prio"
Minimum priority for messages logged to syslog/journal and the console,
respectively.
Values are
\fItrace\fP, \fIdebug\fP, \fIinfo\fP, \fIwarn\fP, \fIerr\fP, and \fIfatal\fP.
Messages with the priority set here or higher get printed to the
respective medium.
Messages printed to stderr are not repeated on stdout.
That allows the local admin to control \fBadduser\fP's chattiness
on the console and in the log independently, keeping probably confusing
information to itself while still leaving helpful information in the log.
stdoutmsglevel, stderrmsglevel, and logmsglevel default to warn, warn, info,
respectively.
.TP
.BR \-v " , " \-\-version
Display version and copyright information.

.SH VALID NAMES
Historically,
\fBadduser\fP(8) and \fBaddgroup\fP(8) enforced
conformity to IEEE Std 1003.1-2001,
which allows only the following characters to appear
in group- and usernames:
letters, digits, underscores, periods, at signs (@) and dashes.
The name may not start with a dash or @.
The "$" sign is allowed at the end of usernames
to allow typical Samba machine accounts.
.PP
The default settings for \fBNAME_REGEX\fP and \fBSYS_NAME_REGEX\fP
allow usernames to contain letters and digits,
plus dash (\-) and underscore (_);
the name must begin with a letter
(or an underscore for system users).
.PP
The least restrictive policy,
available by using the \fB\-\-allow-all-names\fP option,
simply makes the same checks as \fBuseradd\fP(8).
Please note that useradd's checks have become quite a bit more restrictive
in Debian 13.
.PP
Changing the default behavior can be used to create
confusing or misleading names; use with caution.

.SH LOGGING

.B Adduser
uses extensive and configurable logging to tailor its verbosity to
the needs of the system administrator.

Every message that \fBadduser\fR prints has a priority value
assigned by the authors.
This priority can not be changed at run time.
Available priority values are
\fBfatal\fR,
\fBerror\fR,
\fBwarn\fR,
\fBinfo\fR,
\fBdebug\fR,
and
\fBtrace\fR.

If you find that a message has the wrong priority,
please file a bug.

Every time a message is generated,
the code decides whether to print the message to
standard output,
standard error,
or
syslog.
This is mainly and independently controlled by the configuration settings
\fBSTDOUTMSGLEVEL\fR,
\fBSTDERRMSGLEVEL\fR,
and
\fBLOGMSGLEVEL\fR.
For testing purposes,
these settings can be overridden on the command line.

Only messages with a priority higher or equal to the respective
message level are logged to the respective output medium.
A message that was written to standard error is not written
a second time to standard output.

.SH EXIT VALUES

.TP
.B 0
Success: The user or group exists as specified.
This can have 2 causes:
The user or group was created by this call to \fBadduser\fP
or the user or group was already present on the system
as specified before \fBadduser\fP was invoked.
If \fBadduser \-\-system\fP is invoked for a user
already existing with the requested or compatible attributes,
it will also return 0.
.TP
.B 11
The object that \fBadduser\fP was asked to create does already exist.
.TP
.B 12
The object that \fBadduser\fP or \fBdeluser\fP was asked to operate on
does not exist.
.TP
.B 13
The object that \fBadduser\fP or \fBdeluser\fP was asked to operate on
does not have the properties
that are required to complete the operation:
A user (a group) that was requested to be created
as a system user (group)
does already exist and
is not a system user (group),
or
a user (group) that was requested to be created
with a certain UID (GID)
does already exist and
has a different UID (GID),
or
a system user (group) that was requested to be deleted
does exist, but is not a system user (group).
.TP
.B 21
The UID (GID) that was explicitly requested for a new user (group)
is already in use.
.TP
.B 22
There is no available UID (GID) in the requested range.
.TP
.B 23
There is no group with the requested GID for the primary group
for a new user.
.TP
.B 31
The chosen name or comment for a new user or a new group
does not conform to the selected naming rules.
.TP
.B 32
The home directory of a new user must be an absolute path.
.TP
.B 33
useradd returned exit code 19 "invalid user or group name".
That means the user or group name chosen does not fit useradd's restrictions
and adduser cannot create the user.
.TP
.B 41
The group that was requested to be deleted is not empty.
.TP
.B 42
The user that was requested to be removed from a group is
not a member in the first place.
.TP
.B 43
It is not possible to remove a user from its primary group,
or
no primary group selected for a new user by any method.
.TP
.B 51
Incorrect number or order of command line parameters detected.
.TP
.B 52
Incompatible options set in configuration file.
.TP
.B 53
Mutually incompatible command line options detected.
.TP
.B 54
\fBadduser\fP and \fBdeluser\fP invoked as non-root and thus cannot work.
.TP
.B 55
\fBdeluser\fP will refuse to delete the \fIroot\fP account.
.TP
.B 56
A function was requested that needs more packages to be installed.
See Recommends: and Suggests: of the adduser package.
.TP
.B 61
.B Adduser
was aborted for some reason and
tried to roll back the changes that were done during execution.
.TP
.B 62
Internal
.B adduser
error.
This should not happen.
Please try to reproduce the issue and file a bug report.
.TP
.B 71
Error creating and handling the lock.
.TP
.B 72
Error accessing the configuration file(s).
.TP
.B 73
Error accessing a pool file.
.TP
.B 74
Error reading a pool file, syntax error in file.
.TP
.B 75
Error accessing auxiliary files.
.TP
.B 81
An executable that is needed by \fBadduser\fP or \fBdeluser\fP
cannot be found.
Check your installation and dependencies.
.TP
.B 82
Executing an external command returned some unexpected error.
.TP
.B 83
An external command was terminated with a signal.
.TP
.B 84
A syscall terminated with unexpected error.
.PP
Or for many other yet undocumented reasons which
are printed to console then.
You may then consider to increase a log level
to make \fBadduser\fP more verbose.

.SH SECURITY
\fBadduser\fP needs root privileges and offers,
via the \fB\-\-conf\fP command line option
to use different configuration files.
Do not use \fBsudo\fP(8) or similar tools to
give partial privileges to \fBadduser\fP
with restricted command line parameters.
This is easy to circumvent and might
allow users to create arbitrary accounts.
If you want this,
consider writing your own wrapper script
and giving privileges to execute that script.

.SH FILES
.TP
.I /etc/adduser.conf
Default configuration file for \fBadduser\fP(8) and \fBaddgroup\fP(8)
.TP
.I /usr/local/sbin/adduser.local
Optional custom add-ons, see
.BR adduser.local (8)
.

.SH NOTES
Unfortunately, the term
\fIsystem account\fP
suffers from double use in Debian.
It both means an account for the actual Debian system,
distinguishing itself from an \fIapplication account\fP
which might exist in the user database
of some application running on Debian.
A \fIsystem account\fP in this definition has the potential
to log in to the actual system, has a UID,
can be member in system groups,
can own files and processes.
Debian Policy, au contraire, in its Chapter 9.2.2,
makes a distinguishment of
\fIdynamically allocated system users and groups\fP and
\fIdynamically allocated user accounts\fP,
meaning in both cases special instances of \fIsystem accounts\fP.
Care must be taken to not confuse this terminology.
Since \fBadduser\fP and \fBdeluser\fP(8) never address
\fIapplication accounts\fP and
everything in this package concerns \fIsystem accounts\fP here,
the usage of the terms \fIuser account\fP and \fIsystem account\fP
is actually not ambiguous in the context of this package.
For clarity, this document uses the definition
\fIlocal system account or group\fP if the distinction to
\fIapplication accounts\fP or
accounts managed in a directory service is needed.
.PP
\fBadduser\fP used to have the vision to be the universal front end
to the various directory services for
creation and deletion of regular and system accounts in Debian
since the 1990ies.
This vision has been abandoned as of 2022.
The rationale behind this includes:
that in practice,
a small server system is not going to have
write access to an enterprise-wide directory service anyway,
that locally installed packages are hard to manage with
centrally controlled system accounts,
that enterprise directory services have
their own management processes anyway and
that the personpower of the \fBadduser\fP team
is unlikely to be ever strong enough to write and maintain support for
the plethora of directory services that need support.
.PP
\fBadduser\fP will constrict itself to being a policy layer
for the management of local system accounts,
using the tools from the \fBpasswd\fP package for the actual work.
.PP
Group membership changes do not affect processes that are already running.
When a user is added to a group, the new membership becomes effective only for
sessions started after the change.
This behavior is a common source of
confusion for administrators who expect the results of \fBadduser user
group\fP to apply immediately to existing sessions.

To make the new group membership available immediately, the user must
start a new login session.
Alternatively, the
.BR newgrp (1)
command can be used to start a new shell with the updated group
membership.

This behavior is a fundamental property of Unix-like operating systems
and cannot be altered by \fBadduser\fP.

.SH BUGS
Inconsistent use of terminology around the term \fIsystem account\fP
in docs and code is a bug.
Please report this and allow us to improve our docs.
.PP
\fBadduser\fP takes special attention to be directly usable in
Debian maintainer scripts without conditional wrappers,
error suppression and other scaffolding.
The only thing that the package maintainer should need to code
is a check for the presence of the executable in the postrm script.
The \fBadduser\fP maintainers consider the need
for additional scaffolding a bug and
encourage their fellow Debian package maintainers
to file bugs against the \fBadduser\fP package in this case.

.SH SEE ALSO
.BR adduser.conf (5),
.BR deluser (8),
.BR groupadd (8),
.BR useradd (8),
.BR usermod (8),
.B /usr/share/doc/base\-passwd/users\-and\-groups.html
on any Debian system,
Debian Policy 9.2.2,
RFC8264 "PRECIS Framework: Preparation, Enforcement, and Comparison of
Internationalized Strings in Application Protocols",
RFC8265 "PRECIS Representing Usernames and Passwords",
https://wiki.debian.org/UserAccounts.