ERROR:
"show-diff" is not included in the mummer deb package available for Ubuntu 8.10 (mummer v. 3.20-2).
REASON:
The reason might be that show-diff.cc fails to compile (on Ubuntu 8.10 AMD64, src version "3.20", 2007-07-14 00:16):
$ make tigr
[snip]
/usr/bin/g++ -Wall -O3 show-diff.cc tigrinc.o delta.o -o /d/MUMmer3.20/show-diff; chmod 755 /d/MUMmer3.20/show-diff
show-diff.cc: In...
2008-12-17 09:12:29 UTC in MUMmer