Having fun using the ED editor
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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 $
