I think this got deleted because the tests were failing, so let's see what happens!

People can change the `/cygdrive` prefix for mounting Windows drives; `/` and `/mnt` are both popular.  `/proc/cygdrive` is always going to have the drive letters under it.

Got this wrong the first time through

Hopefully this avoids the mismatched directories with saving into a user temporary directory with one user name and reading from a user temporary directory with a different user name.

Echoing the commands in shell scripts in tests causes problems with the tests.