create/update 'HowTo - Beets Music Library Cleanup.md' file

HowTo - Beets Music Library Cleanup.md

@@ -0,0 +1,17 @@
+# Music cleanup one-liners
+
+## Find albums with less than 3 tracks
+Useful for finding directories that contain only artwork
+
+```bash
+NUM=3 && find /mnt/phnas02/music -maxdepth 2 -mindepth 2 -type f -printf '%h\0' | awk -v num="$NUM" 'BEGIN{RS="\0"} {array[$0]++} END{for (line in array) if (array[line]<num) printf "%s\n", line}'
+```
+
+## Beets find and remove albums
+
+Delete album with:
+
+```bash
+beet rm -a "Jon Oliva" -d
+```
+(-a for album and -d to delete the files and not just the database entry)