Simple script to search for cover art with sacad.
Of course, You need sacad = https://github.com/desbma/sacad
At beginning, better check if found properly artist - song names
That's why You can uncomment and comment following two lines.

cd /path/to/music/dir
for i in *.mp3;
  do 
artist=$(echo "$i" |  cut -d '-' -f -1)
album=$(echo "$i" |  cut -d '-' -f 2 | cut -d '[' -f 1 ) 

#echo "${artist}" "${album}" // Uncomment for testing

sacad -v normal "${artist}" "${album}" 200 /path/to/images/dir/"${artist}-${album}.jpg" //Comment this for testing

done