Well if you have mlocate installed, you could do something like:
Code:
updatedb
locate binaryname
Obviously binaryname would be whatever software you're looking for. I guess this might not be the best solution because you'd have to make sure they have mlocate installed.. more dependencies.
Edit: You could also take the approach commonly used by configure scripts when compiling from source: Check in $PATH with something like 'which', if it's not there, tell the user they need to specify the location of the binary with flags like... --mysqldir=/var/lib/mysql