Date: Wed, 22 Apr 1998 20:56:51 +0100 From: Nik Clayton <nik@nothing-going-on.demon.co.uk> To: David Wolfskill <dhw@whistle.com>, freebsd-newbies@FreeBSD.ORG Subject: Re: Eureka! Pasting into netscape Message-ID: <19980422205651.12274@nothing-going-on.org> In-Reply-To: <199804221426.HAA00475@pau-amma.whistle.com>; from David Wolfskill on Wed, Apr 22, 1998 at 07:26:11AM -0700 References: <199804221426.HAA00475@pau-amma.whistle.com>
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On Wed, Apr 22, 1998 at 07:26:11AM -0700, David Wolfskill wrote:
> >...I think I hit power switch about five times
> >(ouch!) before learning that ctrl-alt-backspace will get you out of X :-(
>
> As far as I know, that's a peculiarity of FreeBSD; I've never seen it in
> other UNIX environments... and it's something that I find exceptionally
> counter-intuitive.
Nope. It's a peculiarity of your X setup. You generally only use C-A-B
when your window manager hangs (or something else goes wrong) with your
X server. You can turn this option off with something like
Section "ServerFlags"
DontZap
EndSection
in your XF86Config file (as shown in the XF86Config(5) man page).
If you run X using 'startx', the contents of the xinitrc file are run.
This is either the system xinitrc file or the .xinitrc file in your home
directory, if it exists.
(.)xinitrc is a /bin/sh script. When it ends, your X session ends. It is
customary to use this script to configure your X environment, run a few
XTerms (in the background), and then run your window manager (in the
foreground). This means that your window manager is the last process
started from (.)xinitrc, and since it hasn't quit yet, (.)xinitrc hasn't
finished, which means that X keeps going.
When you shutdown your WM (fvwm, afterstep, twm, whatever) the (.)xinitrc
file keeps going. But there's nothing more for it to do, so it finishes,
so X finishes. This is not the only way to do it. Some people run the
WM in the background, and run xterm (or similar) last, probably with a
different coloured background, or specific title bar. When they exit from
this xterm then their X session ends, regardless of what their WM chose
to do.
Assuming you wanted to work this out from first principles (as I did,
about 4 or 5 years ago at university), your thought processes might
run as follows:
OK, I start X by typing 'startx'. I wonder what actually does? First
thing to do is to find out where that program is stored.
# which startx
/usr/X11R6/bin/startx
That's a start. Now, is this a binary program (in which case I need the
source code to figure out what it's doing) or is it a shell script? If
it's a shell script I can look at it to see what's going on.
# file /usr/X11R6/bin/startx
/usr/X11R6/bin/startx: Bourne shell script text
Good, it's a text file. Lets have a look at it.
# less /usr/X11R6/bin/startx
[snip]
# $XConsortium: startx.cpp,v 1.4 91/08/22 11:41:29 rws Exp $
#
# This is just a sample implementation of a slightly less primitive
# interface than xinit. It looks for user .xinitrc and .xserverrc
# files, then system xinitrc and xserverrc files, else lets xinit choose
# its default. The system xinitrc should probably do things like check
# for .Xresources files and merge them in, startup up a window manager,
# and pop a clock and serveral xterms.
#
# Site administrators are STRONGLY urged to write nicer versions.
#
userclientrc=$HOME/.xinitrc
userserverrc=$HOME/.xserverrc
sysclientrc=/usr/X11R6/lib/X11/xinit/xinitrc
sysserverrc=/usr/X11R6/lib/X11/xinit/xserverrc
[snip]
Well, that's interesting. The comment tells me what it's doing, and it
also helpfully lists the locations of the system wide config files.
This is useful, because if I don't have a .xinitrc file in my home
directory, I can copy the system one to my home directory and modify
it to see what happens. If I screw things up too badly, I can just
delete .xinitrc in my home directory and the system will go back to
its default behaviour. That's a useful safety net.
I can also see that the last line of this script is
xinit $clientargs -- $serverargs
which (after reading the code on the previous lines) indicates that
in the default case of just typing 'startx', the final command run
by this script will be
xinit /usr/X11R6/lib/X11/xinit/xinitrc -- /usr/X11R6/lib/X11/xinit/xserverrc
Continuing our detective hunt, we can now look in the manual page for
xinit(1).
This includes a couple of useful paragraphs:
[snip]
An important point is that programs which are run by
.xinitrc should be run in the background if they do not
exit right away, so that they don't prevent other programs
from starting up. However, the last long-lived program
started (usually a window manager or terminal emulator)
should be left in the foreground so that the script won't
exit (which indicates that the user is done and that xinit
should exit).
[snip]
which is pretty much what I said earlier, and
[snip]
Below is a sample .xinitrc that starts a clock, several
terminals, and leaves the window manager running as the
``last'' application. Assuming that the window manager
has been configured properly, the user then chooses the
``Exit'' menu item to shut down X.
[snip]
and also
[snip]
Another approach is to write a script that starts xinit
with a specific shell script. Such scripts are usually
named x11, xstart, or startx and are a convenient way to
provide a simple interface for novice users:
[snip]
Which seems to cover it all pretty nicely.
Hope that's useful.
N
--
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