Title: Fun tip #3: Split a line using ed

	Title: Fun tip #3: Split a line using ed
	Author: Solène
	Date: 04 December 2018
	Tags: fun-tip unix openbsd
	Description:

	.Dd December 04, 2018
	.Dt "Splitting a line using ed"
	In this new article I will explain how to programmaticaly
	a line (with a newline) using ed.

	We will use commands sent to ed in its stdin to do so. The logic is to
	locate the part where to add the newline and if a character need to be
	replaced.

	.Bd -literal -offset indent
	this is a file
	with a too much line in it that should be split
	but not this one.
	.Ed

	In order to do so, we will format using printf(1) the command list
	using a small trick to insert the newline. The command list is the
	following:

	.Bd -literal -offset indent
	/too much line
	s/that /that\

	,p
	.Ed

	This search the first line matching "too much line" and then replaced
	"that " by "that\n", the trick is to escape using a backslash so the
	substitution command can accept the newline, and at the end we print
	the file (replace ,n by w to write it).

	The resulting command line is:

	.Bd -literal -offset indent
	$ printf '/too much line\ns/that /that\\\n\n,n\n' \| ed file.txt
	81
	> with a too much line in it that should be split
	> should be split
	> 1 this is a file
	2 with a too much line in it that
	3 should be split
	4 but not this one.
	> ?
	.Ed