[feature req] export hash per file

[uprprc777]

It would be great to have the feature to export the hash checksum file one by one for each file instead a collection of all files.

It's very useful.

For example, I may have multiple files and I need to save the checksum for later verification. Also, it would be very likely that I will update some of these files or add and delete files. It would be too slow to generate the checksum one by one, because there is too many. But if I save all checksum in one file, each time there is a update, I have two options. Either manually edit the existed hash collection file, which is very inconvenient and may introduce human errors, or to generate checksum again for all files, which is a huge waste of time and computing resources.