How to add user in a group?
 

Hi,
I have four users in my red hat linux 9. I want that all these four users should add in a group i.e "Marketing".please guide me that using terminal which command may i write so that the users should added in the group.

Note:- I does't want to use GUI interface to do it.

thanks in advance,
garden

Try this:

Substitute john bill mary and jane for your real user names.

thanks for the prompt reply. Well the command works fine. Now a question rises that how can I see all four users in "Marketing " Group. Is there anyway command to check it ?

Use this command:

You may want to use
to make sure you only get exact matches of "Marketing", especially if you want to use it in a script.

-- Dan

thanks a lot all of you for guiding me. Well about users and groups in linux and the files related to it, kindly refer me any site in which I may study it in more detail.

Again thanks
garden

well the command

#cat /etc/group| grep Martketing

and

egrep '^Marketing:' /etc/group

provide same output.So what is the difference in both these and in which situation I may use egrep or cat command.

Iam sure there should be a minor difference.

Man pages will tell you.

Basically grep and egrep is same command, look into the man page for more information.
#man grep

The significance isn't the type of grep used; it's the usage of regexp that is more explicit.

Your example would match more than "Marketing" (e.g. "Marketing2"), that could cause problems when used in scripts.

Nothing like allowing the OP to answer his/her own question, eh? Your answer isn't quite right either.

from the man page:

LOL. I forgot how these discussions can take off. Quite refreshing.

Yes, you're right. Let's get it entirely right:

If you're really using red hat linux 9 (codename Shrike) http://en.wikipedia.org/wiki/Red_Hat_Linux, it hasn't been updated, inc security in years. Do yourself (& us ) a favour an get something current eg http://en.wikipedia.org/wiki/CentOS

I'm sure if he were writing a script he wouldn't be asking for help on adding users to a explicit group... My mind tells me he would know that (or google) already.

Wow. This was an interesting and unexpected first experience of this forum.

So, the command has been corrected as 'egrep' was deprecated according to the man page.

Let's correct the rationale as well:

Tried it and the only group user now belongs to is 'Marketing'. All other group memberships have been removed. Debian Lenny. Any suggestions how I rescue situation?

Try I found the answer in less time than it took to make this post.

You misunderstand. My point was that, with hind sight foolishly, I just did the usermod -G thing. I did it because I could not get the user added to the scanner group.

This was because I was adding ':username' to the end of the scanner line in /etc/group. It should have been ',username'. This is only if there is another name(s) on the end of the line, the first name is indeed seperated by a : .

I was, moderately, complaining about being buggered up in this way.

My point was it is difficult to work out which groups the user should belong to given that all this information has been destroyed.

I was warning people who read this post not to use the idiotic usermod -G command.

So to be bloody idiotic: I am in the right and you are in the wrong.

Not that hard. Could have been solved with a simple google search:

Right, just once more: Using usermod -G removes all existing groups from the user. The above advice in this thread is therefore dangerous and wrong. That is the point I am making.

Disagree
http://linux.die.net/man/8/usermod
See 2nd sentence....

Yes I know but the above thing says 'usermod -G' i.e. no '-a'. So it removes the user from all pre-existing groups. That's all I'm saying. Someone reading this thread might, as I did, do usermod -G thinking they would add the user to a group and not realize they would remove the user from all his other groups. My motive in posting is one of service to other Linux users.:)

Correct. I believe the OP of the advice should edit the post and add the correct method of doing it, so if somebody browsing this runs the first command they see, it won't be as dangerous

I feel vindicated.:D

Oh, haha I wasn't blaming you :D

Hi,
You could have also created the users with the group reference in one commandline.

useradd -g <USER_GROUP> -d <USER_HOME> -c <Some Description> <USERNAME>

This command will only work if the USER_GROUP already exists.
Command to create user group :
groupadd <USER_GROUP>

To answer to your last question, use can use either the 'id' command coupled with the username or grep on the group file as shown.

eg: grep ^<USER_GROUP> /etc/group

eg: id tom
You would need to execute 'id' command for each user.