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 supplemental group(s). Use only with -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.

       -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.
	   The default value is -1.

       -g, --gid GROUP
	   The group name or number of the user's new initial login group. The
	   group name must exist. A group number must refer to an already
	   existing group. The default group number is 1.

       -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
	   name should probably be changed 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.

       -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).

       -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 numerical value of the user's ID. This value must be unique,
	   unless the -o option is used. The value must be non-negative.
	   Values between 0 and 999 are typically reserved for system
	   accounts. Any files which the user owns and which are located in
	   the directory tree rooted at the user's home directory will have
	   the file user ID changed automatically. Files outside of the user's
	   home directory must be altered manually.

       -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.

CAVEATS
       usermod will not allow you to change the name of a user who is logged
       in. 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 is being changed. You must change the owner of any crontab
       files manually. You must change the owner of any at jobs manually. You
       must make any changes involving NIS on the NIS server.

FILES
       /etc/group
	   Group account information.

       /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).



System Management Commands	  10/28/2007			    USERMOD(8)