Increment variable, or set integer value using variable

[joeb5110]

I'm stumped on what should be a simple script. I want to list out extensions in a pbx based on the user input.
It is easy enough for me to prompt and get the first and last extensions and assign them to variables. I can't
figure out how to loop the command from the first to last.
Commands can repeated using integer counts (i = 1000 upto 2000, for example), but how can I set the integer values
from the input? It seems the integer command can only accept numeric values (i.e. I can't say i = first upto last).
Maybe a "while" statement? While extn not xxxx?
This is simple in REXX, but most of the staff uses Procomm. I've beaten my brains out and have to punt on this one.

 

[joeb5110]

I came up with a solution. It's inelegant, but it might be technically correct, i.e. the right way.
Even if not, it works.