Ed: The Standard Editor

4 min read · writing guide

ed was designed for real terminals, i.e. a typewriter. You would type a command to the computer, and it would type out any errors. It would not waste paper, ink, and time by typing out COMMAND RUN SUCCESSFULLY after each command. A silent machine meant a happy machine.

Basic Usage

Open a file:

1ed file.md

Insert a new line.

  1. Press i<Return>
  2. Type the line.
  3. Finish your edit with single dot.
1i
2dear diary,
3.

Print the current line:

1p

Change the current line:

1c
2Dear diary,
3.

Delete the current line:

1d

Write the 'buffer' to disk:

1w

Quit:

1q

Working with Lines

Open that file:

1ed file.md

Add a line:

1a
2Fortune of the day:
3.

Run fortune, and place the results inside the current buffer:

1r!fortune
2?

The ? indicates an error. We can ask what the error was with the command h:

1r!fortune
2?
3h
4Unexpected command suffix

The command r has something after it which makes no sense. It should have a space after the r!

1r !fortune
242

That last line means ed has 42 characters in its buffer.

Read the current line, and show the line number:

1n
22	How many weeks are there in a light year?

This means we are on line 2.

Fill up the file with fortunes:

1r !for x in 1 2 3 ; do echo --- && fortune ; done

Print out which line in the file we are currently on:

1=
212

There are twelve lines. Go back up to line 3:

13
2---

So line 3 just has our delimiter: ---.

Whenever you hit enter, ed prints the current line then moves to the next line.

1I would have promised those terrorists a trip to Disneyland if it would have
2
3gotten the hostages released.  I thank God they were satisfied with the
4
5missiles and we didn't have to go to that extreme.

Go back a few lines:

1-3

Print out 'current line', using the dot:

1.

Print current line with the number of that line:

1.n
211	Possessions increase to fill the space available for their storage.

Print and number the next three lines:

1.,+3n
29	You have no real enemies.
310	------
411	Possessions increase to fill the space available for their storage.

Skip ahead four lines:

1+4
2?
3h
4Invalid address

This is an invalid address because there are no more lines, so ed cannot print them.

All Commands

Meta Commands

Aim Command
Explain an error (?) h
Show a prompt when ed can take a command. P
Change the default filename to rec.txt. f rec.txt
Save the file. w
Append a line after line 8. 8a
Move three lines down. +3
Move four lines back. -4
Move to the last line. $

Create

Aim Command
Insert a line before line 5. 5i
Append a line after line 8. 8a
Read all of ~/.profile into the current position. r ~/.profile
Run dir and place the results into the current position. r !dir
Copy lines 10 to 15 to line 23. 10,15t23

Read

Aim Command
Print current line. . or p
Read lines 1 to 10. 1,10p
Print and number lines 2 to 7. 2,7n
Find the next line ending with fi /fi$/n
Show the number of the next line starting with if. /^if/=
Find the line which contains HOME. ?HOME?
Print the next five lines literally (showing tabs). .,+5l
Print from here till the end of the file. .,$p
Show all lines with HOME and show their numbers. g/HOME/n

Update

Aim Command
On line 30, substitute less with less -R 30s/less/less -R/
Change each line starting # to ## ,s^# /## /g
Move lines 50 to 55 to line 20. 50,55m20

Delete

Aim Command
Delete line 4. 4d
Delete from here to four lines down. `.,+4d
Delete all lines starting with #. g/^#/d