Here's a book on Sed & Awk.
https://doc.lagout.org/operating%20system%20/linux/Sed%20%26%20Awk.pdf
https://stackoverflow.com/questions/7727640/what-are-the-differences-among-grep-awk-sed
"Now awk and sed are completly different than grep. awk and sed are text
processors. Not only do they have the ability to find what you are looking
for in text, they have the ability to remove, add and modify the text as well
(and much more).
awk is mostly used for data extraction and reporting. sed is a stream
editor."
