First create an empty directory to your iPod files, e. g.:
% mkdir ~/iPod
Then create a directory named music
to place your songs:
% mkdir ~/iPod/music
Place all your songs in /music
.
Generate the content based on iPod directory
% docker run -u $UID -w /ipod -v ~/iPod:/ipod dmitryrck/ipod-shuffle-4g -u -t -v /ipod
And sync all content of ~/iPod
to your iPod.
# mount -t vfat /dev/disk/by-uuid/67C3-DCC4 -o uid=1000,gid=1000 /mnt
% find music -type f -iname '*m3u*' -exec rm '{}' \;
% find music -iname '*.mp3' \
-execdir bash -c 'file="{}"; printf "%s\n" "${file##*/}" >> "${PWD##*/}.m3u"' \;
perl-rename 'y/ /_/' *
zmv '(*)' '${(L)1}'
or
perl-rename 'y/A-Z/a-z/' *
% ffmpeg -i filename.m4a -acodec libmp3lame -ab 320k filename.mp3