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SYSUSERS.D(5)                     sysusers.d                     SYSUSERS.D(5)

NAME
       sysusers.d - Declarative allocation of system users and groups
SYNOPSIS
       /usr/lib/sysusers.d/*.conf
DESCRIPTION
       systemd-sysusers uses the files from sysusers.d directory to create
       system users and groups at package installation or boot time. This tool
       may be used to allocate system users and groups only, it is not useful
       for creating non-system users and groups, as it accesses /etc/passwd
       and /etc/group directly, bypassing any more complex user databases, for
       example any database involving NIS or LDAP.
CONFIGURATION FORMAT
       Each configuration file shall be named in the style of package.conf or
       package-part.conf. The second variant should be used when it is
       desirable to make it easy to override just this part of configuration.
       The file format is one line per user or group containing name, ID,
       GECOS field description and home directory:
           # Type Name ID GECOS
           u httpd 440 "HTTP User"
           u authd /usr/bin/authd "Authorization user"
           g input - -
           m authd input
           u root 0 "Superuser" /root
   Type
       The type consists of a single letter. The following line types are
       understood:
       u
           Create a system user and group of the specified name should they
           not exist yet. The user's primary group will be set to the group
           bearing the same name. The user's shell will be set to
           /sbin/nologin, the home directory to the specified home directory,
           or / if none is given. The account will be created disabled, so
           that logins are not allowed.
       g
           Create a system group of the specified name should it not exist
           yet. Note that u implicitly create a matching group. The group will
           be created with no password set.
       m
           Add a user to a group. If the user or group are not existing yet,
           they will be implicitly created.
       r
           Add a range of numeric UIDs/GIDs to the pool to allocate new UIDs
           and GIDs from. If no line of this type is specified the range of
           UIDs/GIDs is set to some compiled-in default. Note that both UIDs
           and GIDs are allocated from the same pool, in order to ensure that
           users and groups of the same name are likely to carry the same
           numeric UID and GID.
   Name
       The name field specifies the user or group name. It should be shorter
       than 31 characters and avoid any non-ASCII characters, and not begin
       with a numeric character. It is strongly recommended to pick user and
       group names that are unlikely to clash with normal users created by the
       administrator. A good scheme to guarantee this is by prefixing all
       system and group names with the underscore, and avoiding too generic
       names.
       For m lines this field should contain the user name to add to a group.
       For lines of type r this field should be set to "-".
   ID
       For u and g the numeric 32bit UID or GID of the user/group. Do not use
       IDs 65535 or 4294967295, as they have special placeholder meanings.
       Specify "-" for automatic UID/GID allocation for the user or group.
       Alternatively, specify an absolute path in the file system. In this
       case the UID/GID is read from the path's owner/group. This is useful to
       create users whose UID/GID match the owners of pre-existing files (such
       as SUID or SGID binaries).
       For m lines this field should contain the group name to add to a user
       to.
       For lines of type r this field should be set to a UID/GID range in the
       format "FROM-TO" where both values are formatted as decimal ASCII
       numbers. Alternatively, a single UID/GID may be specified formatted as
       decimal ASCII numbers.
   GECOS
       A short, descriptive string for users to be created, enclosed in
       quotation marks. Note that this field may not contain colons.
       Only applies to lines of type u and should otherwise be left unset, or
       be set to "-".
   Home Directory
       The home directory for a new system user. If omitted defaults to the
       root directory. It is recommended to not unnecessarily specify home
       directories for system users, unless software strictly requires one to
       be set.
       Only applies to lines of type u and should otherwise be left unset, or
       be set to "-".
CONFIGURATION DIRECTORIES AND PRECEDENCE
       Configuration files are read from directories in /etc/, /run/, and
       /usr/lib/, in order of precedence. Each configuration file in these
       configuration directories shall be named in the style of filename.conf.
       Files in /etc/ override files with the same name in /run/ and
       /usr/lib/. Files in /run/ override files with the same name in
       /usr/lib/.
       Packages should install their configuration files in /usr/lib/. Files
       in /etc/ are reserved for the local administrator, who may use this
       logic to override the configuration files installed by vendor packages.
       All configuration files are sorted by their filename in lexicographic
       order, regardless of which of the directories they reside in. If
       multiple files specify the same option, the entry in the file with the
       lexicographically latest name will take precedence. It is recommended
       to prefix all filenames with a two-digit number and a dash, to simplify
       the ordering of the files.
       If the administrator wants to disable a configuration file supplied by
       the vendor, the recommended way is to place a symlink to /dev/null in
       the configuration directory in /etc/, with the same filename as the
       vendor configuration file.
IDEMPOTENCE
       Note that systemd-sysusers will do nothing if the specified users or
       groups already exist, so normally there no reason to override
       sysusers.d vendor configuration, except to block certain users or
       groups from being created.
SEE ALSO
       systemd(1), systemd-sysusers(8)

systemd 219                                                      SYSUSERS.D(5)