A tool suggestion for moreutils
haschanged
The intention of haschanged is to test whether a file has changed.
It will do this by computing a hash of a file contents and storing that in a file beneath ~/.haschanged.
If a new hash differs from the previously stored hash, or there is no recorded hash it will return
10.If the new hash and the old hash remain the same then the tool will return
01.
The script is trivial, but fairly useful for a lot of things.
The only thing that I don't like is having to store the hash somewhere… (The alternative is to copy the file somewhere, or create "${file}.orig", and then run diff. The latter doesn't work for non-root users wanting to monitor a file in /etc.)