How to list user in Linux box, add an user to a group!

steady_lfcfan · 11-25-2005, 07:42 AM

I have found for time but i still don' know how to list the user in my linux box, also how can I add an exist user to a group!

trevelluk · 11-25-2005, 08:26 AM

To list the users:

cat /etc/passwd | cut -d":" -f1

Hmm, not sure about how to add an existing user to a group though.

pingu · 11-25-2005, 08:38 AM

Depending on distro and desktop, you probably have several gui's to choose from.
Search the menu, or systems control-center (if any), or kde's controlcenter.

Or do it the manual way:
List users:
# cat /etc/passwd
Add user to a group: edit /etc/group Syntax is:
cdrom:x:22

eterh,charles

The user of course has to exist or you'll have problems...

Command-line tools:
useradd and groupadd

steady_lfcfan · 11-25-2005, 07:29 PM

Quote:

Originally posted by steady_lfcfan
I have found for time but i still don' know how to list the user in my linux box, also how can I add an exist user to a group!

thank you, but this print all user includes system user (samba,apache ...)

Pingu, I am running Radhat box and I have not X installed, is there other way?

jrdioko · 11-25-2005, 11:30 PM

See if this helps.

syg00 · 11-25-2005, 11:51 PM

Quote:

Originally posted by steady_lfcfan
... also how can I add an exist user to a group!

"usermod -G ..." ???
See the manpage.

fr4X · 01-16-2008, 07:12 AM

well I see many answered to the listing users,but not so clear answers to adding an existing user to a group (no offense); you can do this by using the "gpasswd -a user group" command.

I know my answer is only a few years late but for googling people it might be nice

B-Con · 01-23-2008, 01:46 AM

As long as the thread got drug up...

Quote:

Originally Posted by syg00

"usermod -G ..." ???
See the manpage.

That's dangerous, since it will REMOVE the user from all current groups and put them ONLY in the specified groups.

Quote:

Originally Posted by manpage

-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. If the user is
currently a member of a group which is not listed, the user will be
removed from the group. This behaviour can be changed via the -a
option, which appends the user to the current supplementary group
list.

Be sure to do -aG, not just -G.

bdeank · 07-26-2009, 11:54 AM

For those following along at home, listing groups can be accomplished in the same way as users:

Code:

cat /etc/group | cut -d":" -f1

mayonaise15 · 01-26-2010, 02:39 PM

Quote:

Originally Posted by steady_lfcfan

thank you, but this print all user includes system user (samba,apache ...)

You will want to search for UIDs in the /etc/passwd file that are greater than 999. The first user account will have the UID 1000, so any account greater than 999 should not be a system account. I recently had to add the group sftponly to a all GIDs above 1000 (so as not to include my own UID on the system). You will want to replace the number 1000 with the starting UID that you want to update and change sftponly to the group name that you want to add. Here is the command that I ran:

Code:

awk -F: '$3 > 1000 {print $1}' /etc/passwd | xargs -I USERNAME sudo usermod -a -G sftponly USERNAME

Weining · 05-03-2010, 03:52 AM

Quote:

Originally Posted by B-Con

As long as the thread got drug up...

That's dangerous, since it will REMOVE the user from all current groups and put them ONLY in the specified groups.

Be sure to do -aG, not just -G.

I tried 'usermod -aG' (at SLES 10, SLES 11), the error comes with:

usermod: invalid option -- 'a'

I tried another option and it works. Since I cannot get any manual/manpage/help about it, you may try it by using non-important user_name first:

usermod -A Group1 user_name

, which adds an existing user 'user_name' to an existing group 'Group1' without changing the group list the user belongs to.

tgs78 · 09-14-2012, 09:18 AM

A very useful bash script to display the detailed user information in Linux

<moderated>

Lunar · 01-27-2013, 01:14 PM

Quote:

Originally Posted by trevelluk

To list the users:

cat /etc/passwd | cut -d":" -f1

Hmm, not sure about how to add an existing user to a group though.

# usermod -G {group-name} username
in SuSE linux, there is No -a (this article states that the '-a' retains existing groups and 'adds' new group '-G'), but in openSuSE 12.2, there is no '-a' option to usermod, it keeps existing groups by default, i guess...

Code:

# id lunar
uid=1002(lunar) gid=100(users) groups=100(users)
# usermod -G sshd lunar
# id lunar
uid=1002(lunar) gid=100(users) groups=100(users),102(sshd)
#

Landis.