This is a suggestion for adding to rsync an option "--checksum-path=PROGRAM".
Once this option is given, provided it is accompained by option "--checksum", both the receiving and sending side of rsync would compute checksums calling PROGRAM, instead of the usual checksum program. Why is this usefull? Suppose I have two collections of MP3 files at different locations which I want to upate. Suppose also that for some reason the testing of modtime is not efficient for distinguishing changeg files. Recall that changes to ID3 tags inside MP3 files do not change filesizes, and hence neither filesize is a good criteria for identifying changes. Suspecting that the changes were made only to ID3 tags, a very common situation, one could write a shell script, say SHORTSUM, which would calculate a checksum only on the first 10K bytes, for example, where ID3 tags reside. Using rsync -av --checksum-path=SHORSUM --checksum /LOCAL-MP3-DIRECTORY/ SERVER:/REMOTE-MP3-DIRECTORY/ would therefore save a lot of processing power. I am aware that rsync was designed in a way to dispense with previous knowledge of how files are structured. However, a simple change as proposed would allow users to custumize rsync based on such knowledge. Sincerely, Ruy Exel -- To unsubscribe or change options: https://lists.samba.org/mailman/listinfo/rsync Before posting, read: http://www.catb.org/~esr/faqs/smart-questions.html
