What is the difference between -g and -G options in useradd After I look through the help. I didn't found much difference between them. > -g, --gid GROUP > > The group name or number of the user's initial login group. The group name must exist. A group number must refer to an already existing group. > > -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. The default is for the user to belong only to the initial group. If they are the same. Why both they exist?

`-g` sets the initial, or primary, group. This is what appears in the group field in `/etc/passwd`. On many distributions the primary group name is the same as the user name.

`-G` sets the supplementary, or additional, groups. These are the groups in `/etc/group` that list your user account. This might include groups such as `sudo`, `staff`, etc.