is it possible to modify the script to print the number at the end of lines begining with LINE, instead of at the start?
Yea, just switch one line of code around:
echo "$LINE $number" >> resultFile
Oh yea, there it goes! 
What about printing it in fixed length files? Meaning can I reserve, say, 10 specific spaces in the line to print this number?
I'm just learning here, btw
Ten specific spaces where? At the end? Not any easy way that I know of, though you could do it with enough programming.. if you know the number is always X digits long, the easiest would just be to stick it at the beginning of the line.
typeset -R10 number
will make number always 10 characters in length. You then need to use quotes to preserve the spaces. Like this...
echo "$number"
the number itself may not always be a specific amount of characters, but it is limited to how many characters it can be, this is up me how many I allow it to be.
For what I'm trying to do (import a fixed length file containing invoices), putting the number at the end or the begining, works fine. I was just curious about 'co-ordinates'
thanks oombera, I owe you many many many pints 