Ubuntu provides several command-line tools for managing groups, but it also provides graphical tools for doing so. Most experienced system administrators prefer the command-line tools because they are quick and easy to use, are always available even when there is no graphic user interface, and because they can be included in scripts she may write if the system administrator wants to write a quick program to perform a repetitive task.
Here are the most commonly used group management command-line tools:
groupadd—This command creates and adds a new group.
groupdel—This command removes an existing group.
groupmod—This command creates a group name or GIDs but doesn’t add or delete members from a group.
gpasswd—This command ...