I just typed r ../how-to-ed/ed-1-intro.txt
 
 And the UNIX first standard editor, ed, loaded for me the article
 you will find behind these lines.  It is about ed, and it will be
 part of larger tutorial or ed, written for people of 2025 who didn't
 use ed when it was all new and flashy.
 
 But you can still use it, as I do on this phlog.  It's incredibly
 compcta and fun, even.
 
 Let's just say I will be adding more to this until I am happy to
 have a complete guide.
 
 ------------------------------------------------------------


 I might be one of the few persons on this wacky world to use ed,
 the UNIX standard editor, regularly. It's a simple, sweet wee
 thing, created by Ken Thompson, no less. If you don't know who
 he's, well long story short, he made contributions to computers
 that are still in use today, 40+ years. He's got a wikipedia
 article, go read it and marvel!

 Anyway, "ed" was designed a long, long time ago, back when the
 average user didn't have a screen.  The computer will literally
 print its output on paper.

 Yeah, paper.

 So you didn't go and print anything that wasn't necessary. Printers
 were noisy, ink and paper gets expensive over time.

 Plus, you just couldn't easily address any random letters. So,
 how can you work with those constrains?

 Well, enter ed.

 A) Very short commands

   Ed commands are short. Usually one character like "p" print or
  "s" substitute

 B) No error messages unless you ask for them.

     Ed is simple enough that, after you've worked with it for a
   little time most error messages will be immediately obvious to
   you.  "Oh, I forgot to tell ed where I wanted to
    save the buffer" Ed prints a "?" to tell you something didn't
  go as expected. If you want the error message just type H. (Or
  run ed with the -H option enable as in ed -H)

 C) Address by lines
     On ed you edit a line or a range of lines.  1d deletes the
   first line, while 1,3s/a/b/g substitues 'a' with 'b' in every
   occurance in the first to the third line, both included.

 D) Pretty advanced search and replace
      Though ed is no baby, it had pretty powerful search and
    replace features.  Simply put it has regular expressions which
    can do incredible things if used correctly.


   On ed, every command is meant to be directed at a line or range
   of lines.  Just as in 2d Delete line two, if exists, if not,
 you'll get the ? error message.  Or 1,$d  Delete from lines 1 to
 the end of the buffer.  (The buffer is your "draft file".  Any
 changes to the buffer won't appear until you write it.  It's the
 w command.