USERMOD(1M)

NAME
usermod - Modify a user account

SYNOPSIS
usermod [ -A method|DEFAULT ] [ -c comment ] [ -d home_dir [ -m ] ] [ -e expire_date ] [ -f inactive_time ] [ -g initial_group ] [ -G group[,...] ] [ -l login_name ] [ -s shell ] [ -u uid [ -o ] login

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

-A method|DEFAULT
    The new value of the user's authentication method. The authentication method is the name of a program which is responsible for validating the user's identity. The string DEFAULT may be used to change the user's authentication method to the standard system password method.

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

-d 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 expire_date
    The date on which the user account will be disabled. The date is specified in the format MM/DD/YY.

-f inactive_days
    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 initial_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 group,[...]
    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

-l login_name
    The name of the user will be changed from login to login_name. Nothing else is changed. In particular, the user's home directory name should probably be changed to reflect the new login name.

-s 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
    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 99 are typically reserved for system accounts. Any files which the user owned must have the file user ID changed manually.

Files
/etc/passwd - user account information
/etc/shadow - secure user account information
/etc/group - group information

SEE ALSO
chfn(1), chsh(1), groupadd(1M), groupdel(1M), groupmod(1M), passwd(1), useradd(1M), userdel(1M)