groupmod 8 System Management Commands groupmod modify a group definition on the system groupmod options GROUP The groupmod command modifies the definition of the specified GROUP by modifying the appropriate entry in the group database. The options which apply to the groupmod command are: -g, --gid GID The group ID of the given GROUP will be changed to GID. The value of GID must be a non-negative decimal integer. This value must be unique, unless the -o option is used. Values between 0 and 999 are typically reserved for system groups. Any files that have the old group ID and must continue to belong to GROUP, must have their group ID changed manually. -h, --help Display help message and exit. -n, --new-name NEW_GROUP The name of the group will be changed from GROUP to NEW_GROUP name. -o, --non-unique When used with the -g option, allow to change the group GID to a non-unique value. /etc/group Group account information. /etc/gshadow Secure group account information. The groupmod command exits with the following values: 0 success 2 invalid command syntax 3 invalid argument to option 4 specified group doesn't exist 6 specified group doesn't exist 9 group name already in use 10 can't update group file chfn1 , chsh1 , passwd1 , gpasswd8 , groupadd8 , groupdel8 , useradd8 , userdel8 , usermod8 .