See the dollar amounts following the program name:
Code:
/mnt/us/extensions/scroller/bin/scroller $1 $2 $3
Their technical name is ARG1, ARG2, ...
That script that you quote (runner.sh) also accepts arguments (in same order) and when it is run the script processor will make the substitution for you.
The Kindles use Ash rather than Bash as the command line processor, which are basically the same, see:
http://www.tldp.org/LDP/abs/abs-guide.pdf
Start at page 30, when you get to and complete the subject begun on page 36, you have the full answer.