Use sha has instead of file size to check for changes

[chriswheeler]

If i'm reading the code correctly, you are currently using the size of the file to check if it has changed.

However, some changes such as a single character will result in the file being the same size, but changed. I'd therefore suggest using sha($file) instead of size($file) to check if it's content has changed.

Also, you probably don't need to write the size/sha has to disk, just store it in a variable and of course don't reboot on the first check.