Having fun using the ED editor
------------------------------

Last edited: $Date: 2018/07/26 18:57:52 $


## Ed is the standard text editor

Ed is a so-called line editor,  was developed by Ken Thompson in the
early days. Ed it was developed  on the PDP-7, build in assembly, to
be used on the PDP-11.

Ed was one of the first parts  of the Unix operating system that was
developed, in August 1969 and was used to write most of the original
Unix code.

See also the nice text on:
http://www.darwinsys.com/history/hist.html.

It is very useful to learn how to  use the Ed editor or at least the
basics.  In  Unix systems,  like  the  family of  Berkeley  Software
Distribution (BSD) systems, Ed is the standard editor. For instance,
the OpenBSD  install image,  that you  can also use  as a  small BSD
system by  dropping a shell, contains  Ed, and you won't  find vi in
this image.  Also, powerful  automation can  be achieved  by feeding
commands from standard input through so-called here-documents.


## Modal editor

Ed is a  modal editor, just like vi (and  ex). After initialisation,
Ed is command  mode. You switch to  insert mode by using  one of the
insert commands,  a (append), c  (change), or i  (insert). Switching
back to command  mode is done by typing a  newline containing only a
single dot (.). This will end the  insert mode and put you back into
command mode.

It is easier  to recognize the mode when you  activate the prompt in
Ed, either by  the command 'P' after initialisation, or  with the -p
flag when starting Ed.


## For fun and profit

So, learning to use Ed can  safe your bacon, and prevent some panic,
when you  have to do some  disaster recovery. Also, you  learn a lot
about using a line editor. Ed and ex (the line editor in vi) are not
that different.

What is  really amazing, is the  raw power that is  already there in
Ed. Ed  supports regular expressions. When  you learn Ed and  use it
for real  work, you get  a glimpse of  the genius of  Ken Thompson.

As far as productivity in writing goes, nothing can beat vi (except,
perhaps, vim). But that  does not mean that you can  not do any real
work  in Ed.  I  recently used  Ed  to write  the  manuscript for  a
complete three-page article for a magazine :)

There are  many good resources that  can help you to  master Ed.


## Use regularly

So, it is useful and fun to learn  and practice to use Ed. Use it at
least once a month for doing some real work, so your Ed-skills won't
get rusty.


$Id: ed.txt,v 1.11 2018/07/26 18:57:52 matto Exp $