A small utility to swap the names of two files.
swap [-v] file1 file2On systems that support RENAME_EXCHANGE (or RENAME_SWAP on macOS) swap will issue a system call that
should make the operation atomic. If this is not the case, swap will rename the first file to a temporary name
while swapping. If there is a failure for some reason while the first file still has the temporary name, swap will not
attempt to undo the operation. I intend for all methods of swapping to be an atomic operation in the future.