Adding 2 lines to Every File in a Directory

Introduction

Quickly wanted to write about a method I used to extract 2 lines from one of my posted and add it to all my other posts.

clip=$(sed -n '5,6p' file-with-option.md)
ls -1 | xargs -i sed -i "4a $clip" {}

Quick explaination. We are saving the lines 5 and 6 from our desired file into $clip.

Then we list all the files without fuzz, pipe them to xargs and set to run the commands individually, appending our $clip variable to line 4