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 users password file comment field. It is
	  normally modified using the chfn(1) utility.

       -d, --home HOME_DIR
	  The users 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 users 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 -a option,
	  which appends 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 users home directory
	  name should probably be changed to reflect the new login name.

       -L, --lock
	  Lock a users password. This puts a ! in front of the encrypted
	  password, effectively disabling the password. You cant 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 users 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 users 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 users home directory will have the file user ID
	  changed automatically. Files outside of the users home directory
	  must be altered manually.

       -U, --unlock
	  Unlock a users password. This removes the ! in front of the
	  encrypted password. You cant 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 users 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	  02/25/2007			    USERMOD(8)