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From: dws@margay.cs.wisc.edu (DaviD W. Sanderson)
Newsgroups: comp.windows.x
Subject: Re: Those Wacky .xsession files
Message-ID: <1991Feb16.013704.21679@spool.cs.wisc.edu>
Date: 16 Feb 91 01:37:04 GMT
References: <9102132312.AA19002@jupiter.saic.com> <9102141614.AA03702@iris49.biosym.com>
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Organization: U of Wisconsin CS Dept
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In article <9102141614.AA03702@iris49.biosym.com> pete@iris49.UUCP (Pete Ware) writes:
>My second guess is that your shell script is getting executing by the
>csh because:
[...]
>	2. xdm is doing something like "/bin/csh -c $HOME/.xsession"
>	   and it's getting read as a csh script.

You can see exactly how it's being run by finding the xdm configuration
files.  For instance, on my workstation the script that xdm runs is
/usr/misc/X11/lib/xdm/Xsession.  Down towards the end it checks
if there is a $HOME/.xsession file and if so, does this:

	exec /bin/csh $HOME/.xsession

In order to get around this problem, I devised the following prologue
for my .xsession file that may come in handy for others, too.

----------------------------------------------------------------------
#!/bin/sh
#-------
# .xsession prologue
#
# This prologue makes sure the subsequent code is run in sh, or ksh if
# it is present.  It is written to work in csh, sh, and ksh.  Specific
# pathnames may have to be altered (or added) if your ksh isn't in /bin.
#
# This prologue is needed since in some installations the .xsession file
# is forcibly run with csh or sh.
#
# DaviD W. Sanderson	15 Feb 1991	(dws@cs.wisc.edu)
#-------
#-------
# If the script is now being executed by csh, look for ksh and try to
# exec it.  Otherwise exec sh.  Note that test -x cannot be used since
# some versions of test do not support the -x option. :-(
#
# The method used is to look for variables that should only be set in
# csh.  This is not perfectly bulletproof, but works well enough for me.
#-------
test "$cwd" != "" && test -f /bin/ksh && exec /bin/ksh $0 $argv:q
test "$cwd" != "" && exec /bin/sh $0 $argv:q
#-------
# At this point the script is being executed by either sh or ksh.
#
# We might have gotten here from sh in the first place (if perhaps the
# .xsession was forcibly run with sh), so see if we are in sh.
# If we are, then see if ksh exists and exec it if it does.
#
# The method used is to look for ~ expansion.  No ~ expansion means sh.
#-------
test "~" = ~      && test -f /bin/ksh && exec /bin/ksh $0 ${1+"$@"}
#-------
# At this point the script is being executed by ksh if it is available,
# otherwise sh.
#-------

# [local configuration]

----------------------------------------------------------------------
-- 
       ___
      / __\  U N S H I N E	           DaviD W. Sanderson
     |  |  | I N E			    dws@cs.wisc.edu
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