sed - Terner's running terminal commands

[sed] Run and understand to display a specific line in a file

[sed] Run and understand: Delete the last line in a file

[sed] Run and understand: Deletes lines within a specified range.

[sed] Run and understand Replace newline at the end of each line

[sed] Run and understand Replace nth arbitrary string in each line

[sed] Run and understand Add a string to a specified line number in a file

[sed] Run and understand Replace a given string with a specified character

Complete Guide to Manipulating Newlines with sed: Insert, Replace, and Delete (Compatible with both BSD and GNU)