No, no intro here.  Just links.

manpage: sed(1)
 - Should suffice to understand the given (short) scripts.

good tutorial: https://www.grymoire.com/Unix/Sed.html
 - Read to write fancy scripts in the Turing complete sed-language yourself.

Notes:
 - I use and assume GNU sed.
   - Other sed implementations may not work with the given scripts (but likely
     will).
