USERMOD(8)                     System Management Commands                    USERMOD(8)

NAME
       usermod - modify a user account

SYNOPSIS
       usermod [options] LOGIN

DESCRIPTION
       The usermod command modifies the system account files to reflect the changes
       that are specified on the command line.

OPTIONS
       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.

       -c, --comment COMMENT
           The new value of the user's password file comment field. It is normally
           modified using the chfn(1) utility.

       -d, --home HOME_DIR
           The user's new login directory.

           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.

       -e, --expiredate EXPIRE_DATE
           The date on which the user account will be disabled. The date is specified
           in the format YYYY-MM-DD.

           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
           The number of days after a password expires until the account is permanently
           disabled.

           A value of 0 disables the account as soon as the password has expired, and a
           value of -1 disables the feature.

           This option requires a /etc/shadow file. A /etc/shadow entry will be created
           if there were none.

       -g, --gid GROUP
           The group name or number of the user's new initial login group. The group
           must exist.

           Any file from the user's home directory owned by the previous primary group
           of the user will be owned by this new group.

           The group ownership of files outside of the user's home directory must be
           fixed manually.

       -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 are subject to the same restrictions as the group given with the
           -g option.

           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
           Move the content of the user's home directory to the new location.

           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
           When used with the -u option, this option allows to change the user ID to a
           non-unique value.

       -p, --password PASSWORD
           The encrypted password, as returned by crypt(3).

           Note: This option is not recommended 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.

           You should make sure the password respects the system's password policy.

       -R, --root CHROOT_DIR
           Apply changes in the CHROOT_DIR directory and use the configuration files
           from the CHROOT_DIR directory.

       -s, --shell SHELL
           The name of the user's new login shell. Setting this field to blank causes
           the system to select the default login shell.

       -u, --uid UID
           The new numerical value of the user's ID.

           This value must be unique, unless the -o option is used. The value must be
           non-negative.

           The user's mailbox, and any files which the user owns and which are located
           in the user's home directory will have the file user ID changed
           automatically.

           The ownership of files outside of the user's home directory must be fixed
           manually.

           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-sub-uids 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
           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-sub-uids 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
           users account. When both --del-sub-uids and --add-sub-uids 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-sub-gids 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
           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-sub-gids 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
           users account. When both --del-sub-gids and --add-sub-gids 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
           The new SELinux user for the user's login.

           A blank SEUSER will remove the SELinux user mapping for user LOGIN (if any).

CAVEATS
       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.

       You must make any changes involving NIS on the NIS server.

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

       MAIL_DIR (string)
           The mail spool directory. This is needed to manipulate the mailbox when its
           corresponding user account is modified or deleted. If not specified, a
           compile-time default is used.

       MAIL_FILE (string)
           Defines the location of the users mail spool files relatively to their home
           directory.

       The MAIL_DIR and MAIL_FILE variables are used by useradd, usermod, and userdel
       to create, move, or delete the user's mail spool.

       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).

           The default value is 0, meaning that there are no limits in the number of
           members in a group.

           This feature (split group) permits to limit the length of lines in the group
           file. This is useful to make sure that lines for NIS groups are not larger
           than 1024 characters.

           If you need to enforce such limit, you can use 25.

           Note: split groups may not be supported by all tools (even in the Shadow
           toolsuite). You should not use this variable unless you really need it.

       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 10000.

       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 10000.

FILES
       /etc/group
           Group account information.

       /etc/gshadow
           Secure group account information.

       /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.

SEE ALSO
       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).

shadow-utils 4.4                       05/17/2017                            USERMOD(8)

Usage: usermod [options] LOGIN

Options:
  -c, --comment COMMENT         new value of the GECOS field
  -d, --home HOME_DIR           new home directory for the user account
  -e, --expiredate EXPIRE_DATE  set account expiration date to EXPIRE_DATE
  -f, --inactive INACTIVE       set password inactive after expiration
                                to INACTIVE
  -g, --gid GROUP               force use GROUP as new primary group
  -G, --groups GROUPS           new list of supplementary GROUPS
  -a, --append                  append the user to the supplemental GROUPS
                                mentioned by the -G option without removing
                                him/her from other groups
  -h, --help                    display this help message and exit
  -l, --login NEW_LOGIN         new value of the login name
  -L, --lock                    lock the user account
  -m, --move-home               move contents of the home directory to the
                                new location (use only with -d)
  -o, --non-unique              allow using duplicate (non-unique) UID
  -p, --password PASSWORD       use encrypted password for the new password
  -R, --root CHROOT_DIR         directory to chroot into
  -s, --shell SHELL             new login shell for the user account
  -u, --uid UID                 new UID for the user account
  -U, --unlock                  unlock the user account
  -v, --add-subuids FIRST-LAST  add range of subordinate uids
  -V, --del-subuids FIRST-LAST  remove range of subordinate uids
  -w, --add-subgids FIRST-LAST  add range of subordinate gids
  -W, --del-subgids FIRST-LAST  remove range of subordinate gids
  -Z, --selinux-user SEUSER     new SELinux user mapping for the user account