The options which apply to the usermod command are:
-a, --append
-b, --badnames
-c, --comment COMMENT
-d, --home HOME_DIR
If the -m option is given, the contents of the current home directory will be moved to the new home directory, which is created if it does not already exist. If the current home directory does not exist the new home directory will not be created.
-e, --expiredate EXPIRE_DATE
An empty EXPIRE_DATE argument will disable the expiration of the account.
This option requires a /etc/shadow file. A /etc/shadow entry will be created if there were none.
-f, --inactive INACTIVE
Ein Wert von 0 deaktiviert das Konto, sobald das Passwort abläuft. Ein Wert von -1 schaltet diese Funktion ab.
This option requires a /etc/shadow file. A /etc/shadow entry will be created if there were none.
-g, --gid GROUP
Jede Datei im Home-Verzeichnis des Benutzers, die der alten Hauptgruppe des Benutzers gehörte, wird dieser neuen Gruppe gehören.
Die Gruppenzugehörigkeit von Dateien außerhalb des Home-Verzeichnisses des Benutzers muss per Hand angepasst werden.
The change of the group ownership of files inside of the user's home directory is also not done if the home dir owner uid is different from the current or new user id. This is safety measure for special home directories such as /.
-G, --groups GROUP1[,GROUP2,...[,GROUPN]]]
If the user is currently a member of a group which is not listed, the user will be removed from the group. This behaviour can be changed via the -a option, which appends the user to the current supplementary group list.
-l, --login NEW_LOGIN
-L, --lock
Note: if you wish to lock the account (not only access with a password), you should also set the EXPIRE_DATE to 1.
-m, --move-home
This option is only valid in combination with the -d (or --home) option.
usermod will try to adapt the ownership of the files and to copy the modes, ACL and extended attributes, but manual changes might be needed afterwards.
-o, --non-unique
-p, --password PASSWORD
Note: This option is not recommended because the password (or encrypted password) will be visible by users listing the processes.
Sie sollten sicherstellen, dass das Passwort den Passwortrichtlinien des Systems entspricht.
-R, --root CHROOT_DIR
-P, --prefix PREFIX_DIR
-s, --shell SHELL
-u, --uid UID
This value must be unique, unless the -o option is used. The value must be non-negative.
Für die Mailbox des Benutzers und alle Dateien, die ihm gehören und sich in seinem Home-Verzeichnis befinden, wird die ID des Eigentümers automatisch angepasst.
Der Eigentümer von Dateien außerhalb des Home-Verzeichnisses des Benutzers muss per Hand angepasst werden.
The change of the user ownership of files inside of the user's home directory is also not done if the home dir owner uid is different from the current or new user id. This is safety measure for special home directories such as /.
No checks will be performed with regard to the UID_MIN, UID_MAX, SYS_UID_MIN, or SYS_UID_MAX from /etc/login.defs.
-U, --unlock
Note: if you wish to unlock the account (not only access with a password), you should also set the EXPIRE_DATE (for example to 99999, or to the EXPIRE value from /etc/default/useradd).
-v, --add-subuids FIRST-LAST
This option may be specified multiple times to add multiple ranges to a users account.
No checks will be performed with regard to SUB_UID_MIN, SUB_UID_MAX, or SUB_UID_COUNT from /etc/login.defs.
-V, --del-subuids FIRST-LAST
This option may be specified multiple times to remove multiple ranges to a users account. When both --del-subuids and --add-subuids are specified, the removal of all subordinate uid ranges happens before any subordinate uid range is added.
No checks will be performed with regard to SUB_UID_MIN, SUB_UID_MAX, or SUB_UID_COUNT from /etc/login.defs.
-w, --add-subgids FIRST-LAST
This option may be specified multiple times to add multiple ranges to a users account.
No checks will be performed with regard to SUB_GID_MIN, SUB_GID_MAX, or SUB_GID_COUNT from /etc/login.defs.
-W, --del-subgids FIRST-LAST
This option may be specified multiple times to remove multiple ranges to a users account. When both --del-subgids and --add-subgids are specified, the removal of all subordinate gid ranges happens before any subordinate gid range is added.
No checks will be performed with regard to SUB_GID_MIN, SUB_GID_MAX, or SUB_GID_COUNT from /etc/login.defs.
-Z, --selinux-user SEUSER
A blank SEUSER will remove the SELinux user mapping for user LOGIN (if any).
You must make certain that the named user is not executing any processes when this command is being executed if the user's numerical user ID, the user's name, or the user's home directory is being changed. usermod checks this on Linux. On other platforms it only uses utmp to check if the user is logged in.
You must change the owner of any crontab files or at jobs manually.
Sie müssen alle Änderung in Bezug auf NIS auf dem NIS-Server vornehmen.
The following configuration variables in /etc/login.defs change the behavior of this tool:
LASTLOG_UID_MAX (number)
No LASTLOG_UID_MAX option present in the configuration means that there is no user ID limit for writing lastlog entries.
MAIL_DIR (string)
MAIL_FILE (string)
The MAIL_DIR and MAIL_FILE variables are used by useradd, usermod, and userdel to create, move, or delete the user's mail spool.
If MAIL_CHECK_ENAB is set to yes, they are also used to define the MAIL environment variable.
MAX_MEMBERS_PER_GROUP (number)
Der Standardwert ist 0, was zur Folge hat, dass die Anzahl der Mitglieder einer Gruppe nicht begrenzt ist.
Diese Fähigkeit (der aufgeteilten Gruppe) ermöglicht es, die Zeilenlänge in der Gruppendatei zu begrenzen. 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: Aufgeteilte Gruppen werden möglicherweise nicht von allen Werkzeugen unterstützt, selbst nicht aus der Shadow-Werkzeugsammlung. Sie sollten diese Variable nur setzen, falls Sie zwingend darauf angewiesen sind.
SUB_GID_MIN (number), SUB_GID_MAX (number), SUB_GID_COUNT (number)
The default values for SUB_GID_MIN, SUB_GID_MAX, SUB_GID_COUNT are respectively 100000, 600100000 and 65536.
SUB_UID_MIN (number), SUB_UID_MAX (number), SUB_UID_COUNT (number)
The default values for SUB_UID_MIN, SUB_UID_MAX, SUB_UID_COUNT are respectively 100000, 600100000 and 65536.
/etc/group
/etc/gshadow
/etc/login.defs
/etc/passwd
/etc/shadow
/etc/subgid
/etc/subuid
chfn(1), chsh(1), passwd(1), crypt(3), gpasswd(8), groupadd(8), groupdel(8), groupmod(8), login.defs(5), subgid(5), subuid(5), useradd(8), userdel(8).