Using KDE3.5 and KDE4

[David Baron <d_baron@012.net.il>]

Now that I can use KDE4, well, it is not quite ready so I still want both 
around. My kde3.5.6 is "konstructed" on /opt/kde3.5 and my kde4 is a Debian 
Sid/experimental installation to /usr (I might have preferred ./opt/kde4 but 
did not want to compile this myself).

I placed kde4.desktop in the appropriate places so I have both the original 
kde and a kde4 on the session menus of the new and old kdm. I also placed 
appropriate exports for paths and env stuff in the startkde scripts.

Problem is that once kde is started, /etc/profile is what is used. I have two 
versions, one with the /opt/kde3.5/bin at the start of the list and one with 
that at the end. The kde session behave differently with these two profiles. 
For example, with the kde3 first, kdesktop and kicker will run in the kde4 
session which dutifully ignores my request to exclude them. With the kde3 
last, then plasma and krunner will attempt to start in a kde3 session and 
promptly crash. Kde3.5 will honor the exclusion but one of my users had the 
entire session crash out (back to logon screen) so I could not set the 
exclusion for her. Where the exclusion info is stored also depends upon 
the /etc/profile.

So ... after this lengthy shpiel, to use both kde versions, the startkde must 
change the profile, not just have that env to itself. Problem is not just 
theoretically there may be more than one user up. If I say only one user at a 
time, changing /etc/profile needs root and startkde runs as user. Would a 
local .profile in $HOME override the /etc/profile in a well-behaved manner 
and should I have startkde copy the appropriate version to $HOME/.profile? Or 
is there a better answer (and should not the installation take care of 
this :-))?