Perl script to check doc_b against doc_a for inconsistence

[satimis]

Hi folks,

I'm going to make a script checking inconsistence on 2 documents, say doc_a and doc_b and have no idea how to start.

doc_b is reproduced from doc_a, (original document) not with 'copy and paste' command.

Making it simple first, as highlighted in following example, an one line document:-

1)
Original document "doc_a"Check this link to sea what scannars are supported by SANE
Already having 2 typing mistakes
sea
scannars

2)
The reproduced document "doc_b" must maintain these 2 mistakes for consistence.
check thes link to sea what scannars are suppurted by SeNE
Unfortunately another 3 typing mistakes were further made;
thes
suppurted
SeNE

What I expect to have in the printout is;
Original Mistake Line No. Word No.
this thes 1 2
supported suppurted 1 9
SANE SeNE 1 11
not just printing out their contents and saying "differ"

Kindly advise how to start. TIA

B.R.
satimis