From NetBSD Wiki

ed is the standard editor :)

Usage

Basic Commands

• Open for editing: e filename
• Exit ed: q
• Save file: w [filename]
• Print the whole file to the terminal: ,p
• The same with line numbering: ,n
• Print a screen at a time: z
• Print some lines 20-40: 20,40p
• Use regex: s/^this/to-that/

Sample ed session

A simple one:

$ ed
a
This is en example text file edited with ed.

Using ed looks scarry at the firs glance,
but it't very comfortable in fact.
.
,p
This is en example text file edited with ed.

Using ed looks scarry at the firs glance,
but it't very comfortable in fact.
w ed.txt
123
q

A bit more realistic:

$ ed
e script.sh
943
/XXX
# XXX this is dirty
n
14      # XXX this is dirty
.,+5n
14      # XXX this is dirty
15      #
16      MENUTMPFILE="/tmp/stat-`date | digest md5`-$RANDOM"
17
18      # showing selecton dialog
19      #
16p
MENUTMPFILE="/tmp/stat-`date | digest md5`-$RANDOM"
16s/`.*`-//
16p
MENUTMPFILE="/tmp/stat-$RANDOM"
14,18n
14      # XXX this is dirty
15      #
16      MENUTMPFILE="/tmp/stat-$RANDOM"
17
18      # showing selecton dialog
14c
# Creatign tmep file
.
14,18n
14      # Creatign tmep file
15      #
16      MENUTMPFILE="/tmp/stat-$RANDOM"
17
18      # showing selecton dialog
u
14c
# Creating temp file
.
14,18n
14      # Creating temp file
15      #
16      MENUTMPFILE="/tmp/stat-$RANDOM"
17
18      # showing selecton dialog
w
924
q