I know that comparing 2 files is a typical problem and there are many discussions on this problem. but I have a rather different problem while working with text files:

I have two text files which may differ in number of lines. now I want to compare two files and find the lines which differ. after that I want to tag all the differencies in both of files. for example here are the content of my files:

File1.txt:

This is the first line.
This line is just appeared in File1.txt.
you can see this line in both files.
this line is also appeared in both files.
this line and,
this one are mereged in File2.txt.
[download]

File2.txt:

This is the first line.
you can see this line in both files.
this line is also appeared in both files.
this line and, this one are mereged in File2.txt.
[download]

After processing I want both files to be like this:

File1.txt:

This is the first line.
<Diff>This line is just appeared in File1.txt.</Diff>
you can see this line in both files.
this line is also appeared in both files.
<Diff>this line and,</Diff>
<Diff>this one are merged in File2.txt.</Diff>
[download]

File2.txt:

This is the first line.
<Diff></Diff>
you can see this line in both files.
this line is also appeared in both files.
<Diff>this line and, this one are mereged in File2.txt.</Diff>
<Diff></Diff>
[download]

How can I do this? I know that some tools such as diff could help me, but how can I convert their results in this format?

Thank you in advance.

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.