Users and Groups

[Michael A Peters]

> Why did someone invent "usermod"? And when you do a ls -l on /dev/ttyS0, 
> the first serial port you notice:
> 
> [root at k5di ~]# ls -al /dev/ttyS0
> crw-rw---- 1 root uucp 4, 64 2007-12-07 04:52 /dev/ttyS0
> [root at k5di ~]#
> 
> The only way I can ever use Com1 is to be root or belong to the uucp Group.

Did you ask how to do that?
I have a file called

/etc/security/console.perms.d/51-custom.perms

It contains the following:
# device classes -- these are shell-style globs
<garmin>=/dev/ttyS0

# permission definitions
<console> 0600 <garmin> 0660 root.uucp



I wrote the file because I have a garmin gps that uses the serial
port, /dev/ttyS0

With that file in place, I do not need to do something dangerous like
add my user to the uucp group.

I wish there was a gui tool to set that kind of thing up, though to be
honest, there are very few device nodes for which you ever need to set
that kind of thing up.