Question

I know that i can chnage the RS =something in awk.

Is there any way i can change the \n RS to something for muliline pattern in sed

Answer 1

Short answer: no, you can’t. Sed reads lines of text, not records with fields.

Depending on the nature of your text, you could use tr to first change all \ns to an unused character and your desired (single-character) record separator to \n. Make the changes you want in sed, then use tr to change the separators back.

You could also manipulate the hold space to let you work with multiple lines of text. This is described in, for example, sed & awk by Dougherty and Robbins.

It’s probably easier just to use awk, though.