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From: bjl@freyr.pttrnl.nl (Ben Lippolt)
Newsgroups: comp.windows.x
Subject: Re: Setting up DISPLAY environment variable
Message-ID: <bjl.647721305@freyr>
Date: 11 Jul 90 18:35:05 GMT
References: <143@percival.albany.edu>
Sender: news@dnlunx.pttrnl.nl
Reply-To: BJ_Lippolt@pttrnl.nl
Lines: 57

narten@percival.albany.edu (Thomas Narten) writes:
>Setting DISPLAY in either .cshrc or .login is asking for trouble.
Not always (see below).

>First, you only want to set DISPLAY to be the name of where
>your X server is running.  The best place to set it is in your
>.xinitrc file, which is executed only when you start up the X server.
This won't work if you use an X-terminal.

[example xrsh deleted]

Another approach is the following: (this is part of my .cshrc)

 || #!/bin/csh
 || # PASS ON the DISPLAY environment variable
 || # (containing the machine name) in case of rlogin
 || # but ONLY IF IT HAS BEEN SET ALREADY (by xinit or something alike)
 || 
 || if ( $TERM =~ xterm%* ) then # XTERM emulator has been started
 ||    setenv DISPLAY `echo $TERM | sed '/xterm%/s///'`
 ||    set term = xterm
 || endif
 || 
 || if ( $TERM == 'xterm' ) then
 ||     if ( $?DISPLAY ) then
 ||         switch( $DISPLAY )
 ||             case "unix:0":
 ||             case "unix:0.0":
 ||             case "local:0.0":
 ||             alias rlogin "(set term=xterm%`hostname`:0;/usr/ucb/rlogin \!*)"
 ||             alias su "(set term = xterm%`hostname`:0; /usr/bin/su \!*)"
 ||             breaksw
 ||         default:
 ||             alias rlogin "(set term=xterm%${DISPLAY}; /usr/ucb/rlogin \!*)"
 ||             alias su "(set term=xterm%${DISPLAY}; /usr/bin/su \|*)"
 ||         endsw
 ||     endif
 || endif

    (The trick is that the environment variable $TERM is not altered during
    a rlogin, so you use it to pass information across rlogins).
This has the advantage that you can run it from X-terminals and it also
works fine with rlogin. In combination with xrsh it should work in all 
conceivable situations.

>-- 
>Thomas Narten
>narten@cs.albany.edu

PS. I didn't invent this. I just copied it from someone else, who copied
it from someone else, who copied it ...

Ben J. Lippolt    
---
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