NetNews Usenet Archive 1992 #31/NN_1992_31.iso/spool/fj/maillis/xwindow/18863

Internet Message Format | 1992-12-22 | 2.5 KB

Path: sparky!uunet!stanford.edu!sun-barr!sh.wide!wnoc-tyo-news!scslwide!wsgw!wsservra!onoe
From: [e-mail] (Mike O'Connor)
Newsgroups: fj.mail-lists.x-window
Subject: Re: setting DISPLAY env variable
Message-ID: <[e-mail]>
Date: 23 Dec 92 02:52:38 GMT
Sender: [e-mail] (Atsushi Onoe)
Distribution: fj
Organization: Not an official spokesperson for Ford Motor Company
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Approved: [e-mail]

Date: 22 Dec 1992 22:17:31 GMT
Message-Id: <[e-mail]>
Newsgroups: comp.windows.x
References: <[e-mail]>, <[e-mail]>
Sender: [e-mail]

Uhhh...  most of these login hacks suffer from the problem that you
have to perform your logins in a different manner, or are site-dependent.
Most of the time, you really don't care how the heck it was that you
accessed your remote site -- you want the DISPLAY to be set anyway.
My hack below doesn't take care of things like multi-headed displays
or logins that don't show up in utmp, and is certainly not of the "one
script for all platforms variety".  But it seems to work with tweaking
here and there with the multitude of platforms I end up connecting to
here at Ford.

The "where you are coming from" information is available in /dev/kmem.
Few users/programs can read /dev/kmem -- it's restricted.  However,
netstat does.  What I typically do is parse the usually-partial
"where you came from" information from who, and compare it against
some netstat output to figure out the IP address of where I'm coming
from.

Here's a script which works under Ultrix, and you'll probably have to
tweak it to work under other platforms.  I have perl scripts which do
this much better, but shell scripts work everywhere, which was kind of
my point.  :)  Set DISPLAY to the output of the script and you should
be set.

#!/usr/bin/sh5
T=`tty | sed 's/.....//'`
H=`who | fgrep $T | awk '{ f=substr($6,2); print f }' | cut -f1 -d\)`
if [ $H = ":0.0" ]
then
    echo "`hostname`:0.0"
else
    H=`echo $H | cut -c1-12`
    J=`netstat -A -f inet | grep $H | head -1 | cut -c-9`
    K=`netstat -A -n -f inet| grep $J | head -1 | awk '{ f=substr($6,1); print f }'`
    G=`echo $K | awk '{ FS="." ; print $1"."$2"."$3"."$4 }'`
    echo $G:0.0
fi
--
 Michael J. O'Connor           |  Internet:  [e-mail]
 Ford Motor Company, OPEO      |  UUCP:      ...!{backbone}!fmsrl7!mjo
 20000 Rotunda, Bldg. 1-3001   |  Phone:     [phone]
 Dearborn, MI  48121           |  Fax:       [phone]