Linux - NewbieThis Linux forum is for members that are new to Linux.
Just starting out and have a question?
If it is not in the man pages or the how-to's this is the place!
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Introduction to Linux - A Hands on Guide
This guide was created as an overview of the Linux Operating System, geared toward new users as an exploration tour and getting started guide, with exercises at the end of each chapter.
For more advanced trainees it can be a desktop reference, and a collection of the base knowledge needed to proceed with system and network administration. This book contains many real life examples derived from the author's experience as a Linux system and network administrator, trainer and consultant. They hope these examples will help you to get a better understanding of the Linux system and that you feel encouraged to try out things on your own.
Click Here to receive this Complete Guide absolutely free.
From the man pages and I made the part important in BOLD:
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.
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
Basically you have to specify all the groups you want them associated with when you use usermod or it doesn't know to keep the existing groups for the user, this is how you would remove them from groups, etc.
I quite frankly find it easier to just edit the /etc/group file.