NOME

usermod - modifica l'account di un utente

SINOSSI

usermod [ opzioni] LOGIN

DESCRIZIONE

The usermod command modifies the system account files.

OPZIONI

The options which apply to the usermod command are:
-a, --append
Add the user to the supplementary group(s). Use only with the -G option.
-b, --badname
Allow names that do not conform to standards.
-c, --comment COMMENT
update the comment field of the user in /etc/passwd, which is normally modified using the chfn(1) utility.
-d, --home HOME_DIR
La nuova directory home dell'utente.
 
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
The date on which the user account will be disabled. The date is specified in the format YYYY-MM-DD. Integers as input are interpreted as days after 1970-01-01.
 
An input of -1 or an empty string will blank the account expiration field in the shadow password file. The account will remain available with no date limit.
 
This option requires a /etc/shadow file. A /etc/shadow entry will be created if there were none.
-f, --inactive INACTIVE
defines the number of days after the password exceeded its maximum age during which the user may still login by immediately replacing the password. This grace period before the account becomes inactive is stored in the shadow password file. An input of 0 will disable an expired password with no delay. An input of -1 will blank the respective field in the shadow password file. See shadow(5) for more information.
 
This option requires a /etc/shadow file. A /etc/shadow entry will be created if there were none.
-g, --gid GROUP
The name or numerical ID of the user's new primary group. The group must exist.
 
Tutti i file nella directory home dell'utente che hanno come gruppo il precedente gruppo primario dell'utente stesso verranno modificati perché abbiano questo nuovo gruppo.
 
Il gruppo dei file che si trovano all'esterno della directory home dell'utente andrà modificato manualmente.
 
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 a safety measure for special home directories such as /.
-G, --groups GROUP1[,GROUP2,...[,GROUPN]]]
A list of supplementary groups which the user is also a member of. Each group is separated from the next by a comma, with no intervening whitespace. The groups must exist.
 
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
The name of the user will be changed from LOGIN to NEW_LOGIN. Nothing else is changed. In particular, the user's home directory or mail spool should probably be renamed manually to reflect the new login name.
-L, --lock
Lock a user's password. This puts a '!' in front of the encrypted password, effectively disabling the password. You can't use this option with -p or -U.
 
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
moves the content of the user's home directory to the new location. If the current home directory does not exist the new home directory will not be created.
 
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
allows to change the user ID to a non-unique value.
 
This option is only valid in combination with the -u option. As a user identity serves as key to map between users on one hand and permissions, file ownerships and other aspects that determine the system's behavior on the other hand, more than one login name will access the account of the given UID.
-p, --password PASSWORD
defines a new password for the user. PASSWORD is expected to be encrypted, as returned by crypt (3).
 
Note: Avoid this option on the command line because the password (or encrypted password) will be visible by users listing the processes.
 
The password will be written in the local /etc/passwd or /etc/shadow file. This might differ from the password database configured in your PAM configuration.
 
Ci si deve accertare che la password rispetti le norme delle password del sistema.
-r, --remove
Remove the user from named supplementary group(s). Use only with the -G option.
-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.
-P, --prefix PREFIX_DIR
Apply changes within the directory tree starting with PREFIX_DIR and use as well the configuration files located there. This option does not chroot and is intended for preparing a cross-compilation target. Some limitations: NIS and LDAP users/groups are not verified. PAM authentication is using the host files. No SELINUX support.
-s, --shell SHELL
changes the user's login shell. An empty string for SHELL blanks the field in /etc/passwd and logs the user into the system's default shell.
-u, --uid UID
The new value of the user's ID.
 
This value must be unique, unless the -o option is used. The value must be non-negative.
 
La casella di posta dell'utente e ogni altro file di proprietà dell'utente che si trovi all'interno della directory home avrà l'ID utente cambiato automaticamente.
 
La proprietà dei file esterni alla directory home dell'utente va corretta manualmente.
 
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 a 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
Unlock a user's password. This removes the '!' in front of the encrypted password. You can't use this option with -p or -L.
 
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
Add a range of subordinate uids to the user's account.
 
This option may be specified multiple times to add multiple ranges to a user's 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
Remove a range of subordinate uids from the user's account.
 
This option may be specified multiple times to remove multiple ranges to a user's 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
Add a range of subordinate gids to the user's account.
 
This option may be specified multiple times to add multiple ranges to a user's 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
Remove a range of subordinate gids from the user's account.
 
This option may be specified multiple times to remove multiple ranges to a user's 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
defines the SELinux user to be mapped with LOGIN. An empty string ("") will remove the respective entry (if any). Note that the shadow system doesn't store the selinux-user, it uses semanage(8) for that.

AVVISI/CAVEAT

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 operating systems 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.
Si devono apportare tutte le modifiche che riguardano NIS sul server NIS.

CONFIGURAZIONE

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

FILE

/etc/group
Group account information
/etc/gshadow
Secure group account informatio.
/etc/login.defs
Shadow password suite configuration
/etc/passwd
User account information
/etc/shadow
Secure user account information
/etc/subgid
Per user subordinate group IDs
/etc/subuid
Per user subordinate user IDs

VEDERE ANCHE

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).