how to search and replace tag text in HTML file based on text instead of line no

Question

How I search for strings with HTML tag like

< link type="text/css" rel="stylesheet" 
                href="https://teststore.xxxx.com/gwtstore.css"> 

In a index.html file and replace that with

<link type="text/css" rel="stylesheet" 
                href="https://testsstore.xxxx.com/gwtstore.css">

Note: I just want to insert 'S' in between teststore.

I did achieved that with perl syntax as

perl -i -p -e 's/teststore/testsstore/ if ($. == 28 || $. == 41)' index.html

My only concern is if the index.html file changes then the line number too will get change.. i dont want my script to exit. instead i need a way to search based on text strings instead of line no.

Any idea how to achive this.. A little brief would be highly helpful.

Answer 1

What you're looking for can be achieved by using "Regular Expressions" or short "Regex". With them you can search for certain text patterns and modify them. It's like a specific language designed to solve "pattern match" and "find & replace" problems mostly used in string parsing.

Perl is actually quite formidable with them as they are integrated in the language itself.

You can find overview e.g. at http://www.troubleshooters.com/codecorn/littperl/perlreg.htm

If you prefer a book: http://regex.info/ (it covers other programming language as well, but mostly covers perl)

Also, as this is a programming topic, you might want to head over to stackoverflow.com and see if anyone has asked anything similar there.