I recently ripped a 7-CD audiobook to listen to on my Sansa Clip+ MP3 player. After a bit of fiddling around with bash I was able to end up with a collection of 183 chapters named 1_01.mp3 through to 7_26.mp3 (the first bit was the disc number, then the track number.)
Simply copying these onto my player didn't work as the tracks were all out of sequence. In the past, with smaller books, I've simply skipped around between the sections to listen in order, but that wasn't going to be an option here.
After some experimenting I discovered the Sansa orders the tracks by the Track Number in the ID3 tag, so I fired off the following bash command to set up the ID3 details appropriately:
n=0 ; for f in *.mp3 ; do n=$((n+1)) ; id3tag --artist="author name" --album="book name" --song="${f/.mp3/}" --track=$n $f ; done
This numbers all the tracks from 1 to 183 in order and also sets the artist and album so I can find it easily in the Audiobook list. The .mp3 is stripped from the displayed filename too.
The id3tag program came from the libid3-3.8.3-dev package, not sure why/when I installed that one...