ADDUSER.CONF(5) File Formats Manual ADDUSER.CONF(5)
NAME
/etc/adduser.conf - configuration file for adduser(8) and addgroup(8).
DESCRIPTION
The file /etc/adduser.conf contains defaults for the programs adduser(8), addgroup(8), deluser(8) and delgroup(8). Each
line holds a single value pair in the form option = value. Double or single quotes are allowed around the value, as is
whitespace around the equals sign. Comment lines must have a hash sign (#) in the first column.
The valid configuration options are:
DSHELL The login shell to be used for all new users. Defaults to /bin/bash.
DHOME The directory in which new home directories should be created. Defaults to /home.
GROUPHOMES
If this is set to yes, the home directories will be created as /home/groupname/user. Defaults to no.
LETTERHOMES
If this is set to yes, then the home directories created will have an extra directory inserted which is the first
letter of the loginname. For example: /home/u/user. Defaults to no.
SKEL The directory from which skeletal user configuration files should be copied. Defaults to /etc/skel.
FIRST_SYSTEM_UID and LAST_SYSTEM_UID
specify an inclusive range of UIDs from which system UIDs can be dynamically allocated. Default to 100 - 999.
Please note that system software, such as the users allocated by the base-passwd package, may assume that UIDs less
than 100 are unallocated.
FIRST_UID and LAST_UID
specify an inclusive range of UIDs from which normal user's UIDs can be dynamically allocated. Default to 1000 -
59999.
FIRST_SYSTEM_GID and LAST_SYSTEM_GID
specify an inclusive range of GIDs from which system GIDs can be dynamically allocated. Default to 100 - 999.
FIRST_GID and LAST_GID
specify an inclusive range of GIDs from which normal group's GIDs can be dynamically allocated. Default to 1000 -
59999.
USERGROUPS
If this is set to yes, then each created non-system user will be given their own group to use. The default is yes.
USERS_GID
USERS_GROUP Defines the group name or GID of the group all newly-created non-system users are placed into. If USER‐
GROUPS is yes, the group will be added as a supplementary group; if USERGROUPS is no,, it will be the primary group.
If you don't want all your users to be in one group, set USERGROUPS is yes, leave USERS_GROUP empty and set USERS_GID
to "-1". The default value of USERS_GROUP is users, which has GID 100 on all Debian systems since it's defined stat‐
ically by the base-passwd package.
DIR_MODE
If set to a valid value (e.g. 0755 or 755), directories created will have the specified permissions mode. Otherwise
2700 is used as default. (See SYS_DIR_MODE for system users.) Note that there are potential configurations (such as
/~user web services, or in-home mail delivery) which will require changes to the default.
SYS_DIR_MODE
If set to a valid value (e.g. 0755 or 755), directories created for system users will have the specified permissions
mode. Otherwise 0755 is used as default. Note that changing the default permissions for system users may cause some
packages to behave unreliably, if the program relies on the default setting.
SETGID_HOME
If this is set to yes, then home directories for users with their own group (USERGROUPS = yes) will have the setgid
bit set. This is the default setting for normal user accounts. If you set this to "no", you should also change the
value of DIR_MODE, as the default (2700) sets this bit regardless. Note that this feature is deprecated and will be
removed in a future version of adduser. Please use DIR_MODE instead.
QUOTAUSER
If set to a nonempty value, new users will have quotas copied from that user. The default is empty.
NAME_REGEX
User and group names are checked against this regular expression. If the name doesn't match this regexp, user and
group creation in adduser is refused unless --allow-badname is set. With --allow-badname set, only weak checks are
performed. The default is the most conservative ^[a-z][-a-z0-9_]*$. See Valid names, below, for more information.
SYS_NAME_REGEX
System user and group names are checked against this regular expression. If this variable is not set, it falls back
to the default value. If the name doesn't match this regexp, system user and group creation in adduser is refused
unless --allow-badname is set. With --allow-badname set, only weak checks are performed. The default is the most con‐
servative ^[a-z_][-a-z0-9_]*$. See Valid names, below, for more information.
SKEL_IGNORE_REGEX
Files in /etc/skel/ are checked against this regex, and not copied to the newly created home directory if they match.
This is by default set to the regular expression matching files left over from unmerged config files
(dpkg-(old|new|dist)).
ADD_EXTRA_GROUPS
Setting this to something other than 0 (the default) will cause adduser to add newly created non-system users to the
list of groups defined by EXTRA_GROUPS (below).
EXTRA_GROUPS
This is the space-separated list of groups that new non-system users will be added to.
NOTES
VALID NAMES
Historically, adduser and addgroup enforced conformity
to IEEE Std 1003.1-2001, which allows only the following characters to appear in group and user names: letters, dig‐
its, underscores, periods, at signs (@) and dashes. The name may not start with a dash or @. The "$" sign is al‐
lowed at the end of usernames (to conform to samba).
The default settings for NAME_REGEXP and SYS_NAME_REGEX
allow usernames to contain lowercase letters and numbers, plus dash (-) and underscore (_); the name must begin with
a letter (or an underscore for system users).
The least restrictive policy, available by using the --allow-all-names
option, simply makes the same checks as useradd: cannot start with a dash, plus sign, or tilde; and cannot contain a
colon, comma, slash, or whitespace.
This option can be used to create confusing or misleading names; use
it with caution.
Please note that regardless of the regular expressions used to evaluate
the username, it may be a maximum of 32 bytes; this may be less than 32 visual characters when using Unicode glyphs
in the username.
FILES
/etc/adduser.conf
SEE ALSO
deluser.conf(5), addgroup(8), adduser(8), delgroup(8), deluser(8)
Debian GNU/Linux ADDUSER.CONF(5)