Did you ever wish to synchronize only the best parts of your music collection to some device? For me it was the case since I had my first MP3-player. Okay, to be honest it was used primarily as an OGG-Player, but that is a diffferent story.
When I bought another device (this time a mobile phone, the Jolla 1), the same demand occured again: I wanted to copy over my most loved music collection to this device. So I scrolled through my collection, syncing things that came to my mind. Album by album, directory by directory. You can imagine this stupid work the following way: Staring at a file manager, starting with the first directory named "A..", let's say ABBA. Have a look at this directory, thinking which album could be nice. Deciding to copy the first one, but not the second one. And then, copy over this music (i.e. wait for a minute or so). Then come back to letter "B..." after this work was done for all artists starting with "A". And the same thing started over again. What was the outcome? I think you can imagine it already: My mobile music collection consists of a lot of artists bearing names early in the alphabet. There is seldom something after "Element of Crime" on my mobile music player systems. Okay, it was 2016 when I sorted my collection the other way around and "Z" enterd the stage.
It was the third device (and ten years after the first music player) that I took the time to see what step I was missing in my so-far rsync usage.
The idea is simple: I want to have a list with the music I like the most. This list should be read by something that puts these files on my music playing device.
And here it comes:
rsync -arv --files-from=essentials.lst musicuser@blabla.berlin:/home/nextcloud/data/jan/files/Music Music/
That's it, this oneliner copies over the music I want from the source I define to the target I find useful. If I want other music, I just add it to the list and do the same command again. If I re-install a device for any reason, I just do the same command again. If I loose a device or buy a better one: You can imagine what I do to make the device feel like home again.
Why do I like it? it is simple, it works for any set of data (think of your wallpapers). The source of truth can be held in a git repo; I can have different flavors (i.e. music-listing_all.lst, essentials.lst, travel2kreta2020.lst, ...)
It could also be a very handy procedure for other scenarios of disaster-recovery: Having a plan that states something like
rsync -arv --files-from=superimportant_data.lst backup@backup-server.com:/var/backup/day-one/
Followed by a
rsync -arv --files-from=not_so_important_but_complete_data.lst backup@backup-server.com:/var/backup/day-one/
sounds reasonable to me. But that is work, syncing music should be fun :)