NEWUSERS(8) System Management Commands NEWUSERS(8)

newusers - erstellt neue oder aktualisiert vorhandene Benutzerkonten in einem Aufruf

ÜBERSICHT

newusers [options] [file]

The newusers command reads a file (or the standard input by default) and uses this information to update a set of existing users or to create new users. Each line is in the same format as the standard password file (see passwd(5)) with the exceptions explained below:

pw_Name:pw_Passwort:pw_Benutzerkennung:pw_Gruppenkennung:pw_GECOS:pw_Verzeichnis:pw_Shell

pw_name

Dies ist der Anmeldename des Benutzers.

It can be the name of a new user or the name of an existing user (or a user created before by newusers). In case of an existing user, the user's information will be changed, otherwise a new user will be created.

pw_passwd

If this field is not empty, it will be encrypted and used as the new value of the encrypted password.

pw_uid

Mit diesem Feld wird die Benutzerkennung festgelegt.

If the field is empty, a new (unused) UID will be defined automatically by newusers.

Wenn dieses Feld eine Zahl enthält, wird sie als Benutzerkennung übernommen.

If this field contains the name of an existing user (or the name of a user created before by newusers), the UID of the specified user will be used.

Falls die Kennung eines bestehenden Benutzers verändert wird, muss bei den Dateien des Benutzers der Eigentümer per Hand angepasst werden.

pw_gid

Mit diesem Feld wird die Kennung der primären Gruppe des Benutzers festgelegt.

If this field contains the name of an existing group (or a group created before by newusers), the GID of this group will be used as the primary group ID for the user.

Wenn dieses Feld eine Zahl enthält, wird sie als Kennung der primären Gruppe des Benutzers verwendet. Falls keine Gruppe mit dieser Kennung existiert, wird eine neue Gruppe mit dieser Kennung und dem Namen des Benutzers erstellt.

If this field is empty, a new group will be created with the name of the user and a GID will be automatically defined by newusers to be used as the primary group ID for the user and as the GID for the new group.

If this field contains the name of a group which does not exist (and was not created before by newusers), a new group will be created with the specified name and a GID will be automatically defined by newusers to be used as the primary group ID for the user and GID for the new group.

pw_gecos

Dieses Feld wird in das GECOS-Feld des Benutzers kopiert.

pw_dir

In diesem Feld wird das persönliche Verzeichnis des Benutzers definiert.

If this field does not specify an existing directory, the specified directory is created, with ownership set to the user being created or updated and its primary group. Note that newusers does not create parent directories of the new user's home directory. The newusers command will fail to create the home directory if the parent directories do not exist, and will send a message to stderr informing the user of the failure. The newusers command will not halt or return a failure to the calling shell if it fails to create the home directory, it will continue to process the batch of new users specified.

If the home directory of an existing user is changed, newusers does not move or copy the content of the old directory to the new location. This should be done manually.

pw_shell

Mit diesem Feld wird die Shell des Benutzers festgelegt, wobei diese Eingabe nicht überprüft wird.

newusers first tries to create or change all the specified users, and then write these changes to the user or group databases. If an error occurs (except in the final writes to the databases), no changes are committed to the databases.

Im ersten Durchlauf werden Benutzer mit einem gesperrten Passwort erstellt und Passwörter von bereits vorhandenen Benutzern werden nicht verändert. Im zweiten Durchlauf werden die Passwörter mit PAM aktualisiert. Sofern dabei ein Fehler auftritt, wird dieser angezeigt, die Aktualisierung der übrigen Passwörter aber fortgesetzt.

Dieser Befehl ist für weitreichende Systeme gedacht, bei denenviele Konten gleichzeitig angelegt werden müssen.

The options which apply to the newusers command are:

--badname 

erlaube Namen, die nicht den Standards entsprechen.

-h, --help

zeigt die Hilfe an und beendet das Programm.

-r, --system

erstellt ein Systemkonto

System users will be created with no aging information in /etc/shadow, and their numeric identifiers are chosen in the SYS_UID_MIN-SYS_UID_MAX range, defined in login.defs, instead of UID_MIN-UID_MAX (and their GID counterparts for the creation of groups).

-R, --root CHROOT_DIR

Apply changes in the CHROOT_DIR directory and use the configuration files from the CHROOT_DIR directory. Only absolute paths are supported. No SELINUX support.

Die Eingabedatei muss geschützt werden, da sie unverschlüsselte Passwörter enthält.

The following configuration variables in /etc/login.defs change the behavior of this tool:

GID_MAX (number), GID_MIN (number)

Range of group IDs used for the creation of regular groups by useradd, groupadd, or newusers.

The default value for GID_MIN (resp. GID_MAX) is 1000 (resp. 60000).

HOME_MODE (number)

The mode for new home directories. If not specified, the UMASK is used to create the mode.

useradd and newusers use this to set the mode of the home directory they create.

MAX_MEMBERS_PER_GROUP (number)

Maximum members per group entry. When the maximum is reached, a new group entry (line) is started in /etc/group (with the same name, same password, and same GID).

Der Standardwert ist 0, was bedeutet, dass die Anzahl der Mitglieder einer Gruppe nicht begrenzt ist.

Das Aufteilen von Gruppen ermöglicht es, Längenvorgaben für die Zeilen der Gruppendatei einzuhalten. Damit kann sichergestellt werden, dass die Zeilen für NIS-Gruppen nicht länger als 1024 Zeichen sind.

Falls Sie eine solche Begrenzung benötigen, können Sie 25 verwenden.

Hinweis: Mit aufgeteilten Gruppen können möglicherweise nicht alle Hilfsprogramme (nicht einmal jene der Shadow-Programmsammlung) umgehen. Sie sollten diese Variable nur setzen, wenn Sie sie wirklich benötigen.

PASS_MAX_DAYS (number)

die maximale Anzahl von Tagen, die ein Passwort verwendet werden darf. Wenn das Passwort älter ist, wird ein Wechsel des Passworts erzwungen. Falls nicht definiert, wird -1 angenommen, womit Passwörter unbefristet gelten.

PASS_WARN_AGE (number)

The number of days warning given before a password expires. A zero means warning is given only upon the day of expiration, a value of -1 means no warning is given. If not specified, no warning will be provided.

SUB_GID_MIN (number), SUB_GID_MAX (number), SUB_GID_COUNT (number)

If /etc/subuid exists, the commands useradd and newusers (unless the user already have subordinate group IDs) allocate SUB_GID_COUNT unused group IDs from the range SUB_GID_MIN to SUB_GID_MAX for each new user.

The default values for SUB_GID_MIN, SUB_GID_MAX, SUB_GID_COUNT are respectively 100000, 600100000 and 65536.

SUB_GID_DETERMINISTIC (boolean)

If set to yes, the commands useradd, usermod, and newusers will calculate subordinate GID ranges deterministically based on the user's UID instead of searching for the next free range. The formula used is: 
      start = SUB_GID_MIN + ((UID - UID_MIN) * SUB_GID_COUNT)
      end   = start + SUB_GID_COUNT - 1

This ensures the same UID always receives the same subordinate GID range on every system, making it suitable for environments with centralized user management (LDAP, NIS, etc.) or synchronized UIDs across systems.

If SUB_GID_DETERMINISTIC is enabled, you can use usermod --add-subgids -S to produce deterministic subgids.

WARNING: Because UID_MIN is used to calculate the ranges, any change of UID_MIN will change the ranges calculated. SUB_GID_COUNT is used to calculate the ranges, any change of SUB_GID_COUNT will change the ranges calculated. Users with identities less than UID_MIN are incompatible with SUB_GID_DETERMINISTIC, but can still be set manually.

WARNING: Do not mix deterministic and linear (default) allocation on the same system or across systems sharing /etc/subgid via network storage (NFS, etc.). Mixing allocation methods will cause subordinate ID range conflicts and overlaps .

The default value for SUB_GID_DETERMINISTIC is no.

Range Calculation Examples

With default configuration (UID_MIN=1000, SUB_GID_MIN=100000, SUB_GID_COUNT=65536):

UID Calculation Subordinate GID Range
1000 100000 + ((1000-1000) * 65536) 100000-165535
1001 100000 + ((1001-1000) * 65536) 165536-231071
1002 100000 + ((1002-1000) * 65536) 231072-296607
1100 100000 + ((1100-1000) * 65536) 6653600-6719135

Subordinate ID Space Planning

When planning subordinate ID allocation, calculate the maximum number of users the space can accommodate:

      capacity = (SUB_GID_MAX - SUB_GID_MIN) / SUB_GID_COUNT

With default values: (600100000 - 100000) / 65536 ≈ 9155 users.

For high-density environments with many users and smaller allocations:

        SUB_GID_COUNT  4096
        SUB_GID_MIN    100000
        SUB_GID_MAX    10000000

This gives: (10000000 - 100000) / 4096 ≈ 2417 users.

UNSAFE_SUB_GID_DETERMINISTIC_WRAP (boolean)

WARNING: SECURITY RISK - MAY CAUSE RANGE OVERLAPS AND PRIVILEGE ESCALATION!

Only effective when SUB_GID_DETERMINISTIC is set to yes.

When set to yes (WRAP MODE), allows the deterministic range calculation to wrap around using modulo arithmetic when a UID would overflow the configured subordinate ID space. The subordinate ID space is treated as a ring buffer.

WARNING: Range overlaps can lead to container escapes and privilege escalation. For example, with SUB_GID_MIN=100000, SUB_GID_MAX=200000, SUB_GID_COUNT=65536, User A (UID 1000) gets range [100000, 165535] and User B (UID 1001) wraps and overlaps with User A. User B's container can now access files from User A's containers.

Use only in development, testing, or tightly constrained lab environments.

When set to no (default), any arithmetic overflow or range exceeding SUB_GID_MAX is a hard error. This guarantees non-overlapping, monotonic allocation.

The default value for UNSAFE_SUB_GID_DETERMINISTIC_WRAP is no.

SUB_UID_MIN (number), SUB_UID_MAX (number), SUB_UID_COUNT (number)

If /etc/subuid exists, the commands useradd and newusers (unless the user already have subordinate user IDs) allocate SUB_UID_COUNT unused user IDs from the range SUB_UID_MIN to SUB_UID_MAX for each new user.

The default values for SUB_UID_MIN, SUB_UID_MAX, SUB_UID_COUNT are respectively 100000, 600100000 and 65536.

SUB_UID_DETERMINISTIC (boolean)

If set to yes, the commands useradd, usermod, and newusers will calculate subordinate UID ranges deterministically based on the user's UID instead of searching for the next free range. The formula used is: 
      start = SUB_UID_MIN + ((UID - UID_MIN) * SUB_UID_COUNT)
      end   = start + SUB_UID_COUNT - 1

This ensures the same UID always receives the same subordinate UID range on every system, making it suitable for environments with centralized user management (LDAP, NIS, etc.) or synchronized UIDs across systems.

If SUB_UID_DETERMINISTIC is enabled, you can use usermod --add-subuids -S to produce deterministic subuids.

WARNING: Because UID_MIN is used to calculate the ranges, any change of UID_MIN will change the ranges calculated. SUB_UID_COUNT is used to calculate the ranges, any change of SUB_UID_COUNT will change the ranges calculated. Users with identities less than UID_MIN are incompatible with SUB_UID_DETERMINISTIC, but can still be set manually.

WARNING: Do not mix deterministic and linear (default) allocation on the same system or across systems sharing /etc/subuid via network storage (NFS, etc.). Mixing allocation methods will cause subordinate ID range conflicts and overlaps .

The default value for SUB_UID_DETERMINISTIC is no.

Range Calculation Examples

With default configuration (UID_MIN=1000, SUB_UID_MIN=100000, SUB_UID_COUNT=65536):

UID Calculation Subordinate UID Range
1000 100000 + ((1000-1000) * 65536) 100000-165535
1001 100000 + ((1001-1000) * 65536) 165536-231071
1002 100000 + ((1002-1000) * 65536) 231072-296607
1100 100000 + ((1100-1000) * 65536) 6653600-6719135

Subordinate ID Space Planning

When planning subordinate ID allocation, calculate the maximum number of users the space can accommodate:

      capacity = (SUB_UID_MAX - SUB_UID_MIN) / SUB_UID_COUNT

With default values: (600100000 - 100000) / 65536 ≈ 9155 users.

For high-density environments with many users and smaller allocations:

        SUB_UID_COUNT  4096
        SUB_UID_MIN    100000
        SUB_UID_MAX    10000000

This gives: (10000000 - 100000) / 4096 ≈ 2417 users.

UNSAFE_SUB_UID_DETERMINISTIC_WRAP (boolean)

WARNING: SECURITY RISK - MAY CAUSE RANGE OVERLAPS AND PRIVILEGE ESCALATION!

Only effective when SUB_UID_DETERMINISTIC is set to yes.

When set to yes (WRAP MODE), allows the deterministic range calculation to wrap around using modulo arithmetic when a UID would overflow the configured subordinate ID space. The subordinate ID space is treated as a ring buffer.

WARNING: Range overlaps can lead to container escapes and privilege escalation. For example, with SUB_UID_MIN=100000, SUB_UID_MAX=200000, SUB_UID_COUNT=65536, User A (UID 1000) gets range [100000, 165535] and User B (UID 1001) wraps and overlaps with User A. User B's container can now access files from User A's containers.

Use only in development, testing, or tightly constrained lab environments.

When set to no (default), any arithmetic overflow or range exceeding SUB_UID_MAX is a hard error. This guarantees non-overlapping, monotonic allocation.

The default value for UNSAFE_SUB_UID_DETERMINISTIC_WRAP is no.

SYS_GID_MAX (number), SYS_GID_MIN (number)

Range of group IDs used for the creation of system groups by useradd, groupadd, or newusers.

The default value for SYS_GID_MIN (resp. SYS_GID_MAX) is 101 (resp. GID_MIN-1).

SYS_UID_MAX (number), SYS_UID_MIN (number)

Range of user IDs used for the creation of system users by useradd or newusers.

The default value for SYS_UID_MIN (resp. SYS_UID_MAX) is 101 (resp. UID_MIN-1).

UID_MAX (number), UID_MIN (number)

Range of user IDs used for the creation of regular users by useradd or newusers.

The default value for UID_MIN (resp. UID_MAX) is 1000 (resp. 60000).

UMASK (number)

Die Maske zum Berechtigungsmodus neu erstellter Dateien, siehe umask(2)Falls nicht angegeben, wird 022 verwendet. Somit werden die Dateien und Verzeichnisse des Benutzers mit dem Modus 755 beziehungsweise dem Zugriffsmuster rwxr-wr-x angelegt.

useradd and newusers use this mask to set the mode of the home directory they create if HOME_MODE is not set.

It is also used by pam_umask as the default umask value.

/etc/passwd

Informationen zu den Benutzerkonten

/etc/shadow

geschützte Informationen zu den Benutzerkonten

/etc/group

Informationen zu den Gruppenkonten

/etc/gshadow

geschützte Informationen zu den Gruppenkonten

/etc/login.defs

konfiguriert die Shadow-Hilfsprogramme.

/etc/pam.d/newusers

PAM configuration for newusers.

/etc/subgid

enthält untergeordnete Gruppenkennungen der einzelnen Benutzer.

/etc/subuid

enthält untergeordnete Benutzerkennungen der einzelnen Benutzer.

login.defs(5), passwd(1), subgid(5), subuid(5), useradd(8).

30.07.2026 shadow-utils 4.20.0