I use 'convert' with a simple bash for loop quite a bit to do various tasks.
Code:
for i in *.jpg ;
do
convert $i `basename .jpg $i`.gif
done
You can also use this trick to, for example, make thumbnails
Code:
for i in *.jpg ;
do
convert -size 640x480 $i `basename .jpg $i`-small.jpg
done