(In the installer, I chose to install it to ~/games/rtcw rather than /usr/local.)
All the files were owned by root, so I chmoded them to me:
chmod -R sacha:sacha .
5. Read the INSTALL file it installs.
Next, I installed the Windows version with wine.
6. Insert disc 1, and wait for Linux to mount it.
7. Run the Windows installer:
A graphical dialog appears with some buttons; click through
On my machine, at this point I just got a black screen with some mis-rendered text at the top left. I thought it was bust, but actually it's the CD key dialog. (If you hit Esc a quit dialog appears, giving some clues.)
8. Enter the CD key (sticker on the inside of the DVD case, on mine at least) and hit Enter twice.
9. Click through the Windows installer, accepting the defaults.
10. At a certain point it asks for disc 2. You can't just eject the CD; in your terminal, type
Stick in disc 2 and wait for Linux to mount the CD before clicking OK in the Windows installer, or you'll get an error.
Do the same when it asks you for disc 1 again.
Towards the end of the install the Windows installer reported some I/O errors; I don't know if this was a real problem with my discs. In any case, it had installed the files I needed, so I just bailed out (without accepting the Rollback option the installer offers).
11. Copy the files you need:
cd ~/.wine/drive_c/Program\ Files/Return*/Main
cp -p pak0.pk3 sp_pak1.pk3 mp_pak0.pk3 ~/games/rtcw/main/
12. Run it!
One last thing: I have a widescreen monitor (1680x1050). Wolf doesn't list this in its System options. To set it as the default resolution, create or edit the file