in reply to Determine new line number in revised file given old line number
Version1.txt
Line1 Line2 Line3 Line4 [download]
Version2.txt
Line1 Line3 Linenew Linenewagain Line4 [download]
updated_line_number.pl Version1.txt Version2.txt 1 1 updated_line_number.pl Version1.txt Version2.txt 2 0 updated_line_number.pl Version1.txt Version2.txt 3 2 updated_line_number.pl Version1.txt Version2.txt 4 5 [download]