picard: renaming files

wiki/music.md

@@ -24,7 +24,7 @@ This way you don't have to search for your CDs all the time.
 - [metaflac](./linux/flac.md) for linux is a programm
   to edit the tags of flac files from the command line.
   It is bundled in the `flac` package for debian and arch based systems.
-- [MusicBrainz Picard](https://picard.musicbrainz.org/) for linux is a
+- [MusicBrainz Picard](./picard.md) for linux is a
   graphical user interface for tagging files of many different formats.
 
 ## Working with flac files on Linux

wiki/picard.md

@@ -0,0 +1,26 @@
+# Picard
+
+[MusicBrainz Picard](https://picard.musicbrainz.org/) is a free cross-platform
+tagging software for music.
+
+## File naming
+
+To enable the file renaming on saving check `Rename files when saving` in the preferences
+
+Under `Options` you can `Open file naming script editor` to change the script.
+
+The following is a basic script for renaming files to the scheme
+`[<discnumber>.]<tracknumber>._<artist>_-_<title>`
+all in lower case.
+discnumber is only added, when the total disc count is greater than 1.
+Both discnumber and tracknumber are padded according to the number of total
+discs and tracks.
+The tracknumber is padded to at least 2 places.
+
+```
+$replace($lower(
+$if($gt(%totaldiscs%,1.),$num(%discnumber%,$len(%totaldiscs%)).,)
+$num(%tracknumber%,$if($gt($len(%totaltracks%),2),$len(%totaltracks%),2))._
+%artist%_-_
+%title%), ,_)
+```