Users and Groups

[Robert P. J. Day]

On Fri, 7 Dec 2007, Karl Larsen wrote:

> Robert P. J. Day wrote:

> > but there's a *reason* it's done this way, karl.  typically, when
> > you start adding new users, you're not going to add them to the
> > system groups.

>    I was not adding a new user or group.

that's not the point.  you were complaining originally that you
couldn't see all the users and groups on the system.  and i explained
why that's actually a good thing -- because, for the most part, you
shouldn't *need* to see those users or groups, unless you're doing
something unusual.

if you truly need to see them, then it's a simple mouse click.  but
unless you do, there's no need to have them cluttering up your dialog
box.  do you see the point i'm trying to make?

> 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.

not necessarily.  depending on how you access that port, it might have
its attributes changed to match yours automatically.  from my system:

$ ls -l /dev/console
crw------- 1 rpjday root 5, 1 2007-12-06 03:17 /dev/console

notice how i'm the owner of /dev/console?  i never changed that
ownership -- that was done for me based on the fact that that's how i
logged in.  and if you run an application that needs to access the
serial port, that *application* might do that for you automatically as
well.

if you truly want to access the serial port directly, then, yes, you
might need to change its attributes, but that doesn't mean you *need*
to add yourself to the uucp group -- it just means you need to change
the owner or group on the serial port temporarily.  that's probably
going to be a lot easier than adding yourself to system groups.

> >   you generally need a really good reason to add a user to a
> > system group.
> >
>    I and many others will find really good reasons.

no, karl ... you might find *a* reason.  but it won't be a good one.
as i pointed out above, there is a much easier way to accomplish what
you're trying to do.

rday

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Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry
Waterloo, Ontario, CANADA

http://crashcourse.ca
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