audio software for linux

[Lockhart, Charles]

Anybody know of some good audio editing software for linux?  I've been asked
to convert some tapes of a course taught 25 years ago to cd/digital format,
and there's all this background noise, the teacher walking away from the
recorder, etc., and I'm looking for a something that will fix this up.

Also, in case anybody's done this, any hints as to the best way?  So far
I've just been playing them from my tapedeck into my soundcard, but I worry
that some of the signal is getting clipped.

-Charles Lockhart