The question I was asking was why did this install delete /bin/bash, and the /bin/sh symlink (which shouldn't
have been touched at all) .
I know that bash is supposed to install to /bin; however, almost all, if not all, GNU sources of any program
default to installing under /usr/local/ (this makes it possible to have installed, for example, two different versions
of some programs (one under /usr/local and one under /usr or / for example), necessary in case of problems
with the new version). I could have added --prefix=/ (to get the new version to install directly to /bin) to
the ./configure command line, but didn't want to replace the existing bash until the new build was tested.
As I used the GNU defaults for configure, the new bash installed to /usr/local/bin, and should not have
touched anything at all in /bin. My only immediate mistake was failing to copy the new bash immediately
to /bin before rebooting, and if I had done that, I would not have discovered that the original /bin/bash
had disappeared (though with /bin/sh -> bash gone, the lack of sh would have been noticed quickly!)
If I had not had at least one emergency rescue disk available (I've got Knoppix, Tom's RTBT & LinuxCare
Rescue), I'd have had to re-install and re-build the entire 6.1 distribution.