An equivalent way of perform this statement:

ELAPSED=$(($FINISH – $START))

with bash/ksh is using the let keyword:

let ELAPSED="FINISH – START"

It's a personal choice, but most shell programmers tend to use the method you intially introduced.

You can also set expression entirely withn parenthesis and elimiante some $

((ELAPSED=FINISH – START))

Again, it's personal preference

Finally, in shell programming, it's typical to have to increase/decrease a counter – say by 1. this works:

cnt=0
((cnt=cnt+1))
echo $cnt # should equal 1

alternatively, similar to "C" you could do this:

cnt=0
((cnt+=1))

Just thought you'd like to know.