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usermod


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. 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.

           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.

           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.
           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
           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.

           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.
           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
           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).

       -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, but only check if the user is
       logged in according to utmp on other architectures.

       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.

       If MAIL_CHECK_ENAB is set to yes, they are also used to define the MAIL
       environment variable.

           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.


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.


SEE ALSO

       chfn(1), chsh(1), passwd(1), crypt(3), gpasswd(8), groupadd(8),
       groupdel(8), groupmod(8), login.defs(5), useradd(8), userdel(8).


shadow-utils 4.1.5.1 11/05/2016 USERMOD(8)



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