Unix Notes Utilities Notes

Sed – An Introduction and Tutorial

Sed is the ultimate stream editor. If that sounds strange, picture a stream flowing through a pipe. Okay, you can't see a stream if it's inside a pipe. That's what I get for attempting a flowing analogy. You want literature, read James Joyce.

Anyhow, sed is a marvelous utility. Unfortunately, most people never learn its real power. The language is very simple, but the documentation is terrible. The Solaris on-line manual pages for sed are five pages long, and two of those pages describe the 34 different errors you can get. A program that spends as much space documenting the errors than it does documenting the language has a serious learning curve.

Do not fret! It is not your fault you don't understand sed. I will cover sed completely. But I will describe the features in the order that I learned them. I didn't learn everything at once. You don't need to either.

Sed – An Introduction and Tutorial.

4 replies on “Sed – An Introduction and Tutorial”

I spotted about a dozen small grammar errors on your otherwise excellent sed tutorial:

This chapter, like all of the rest, start (should be: starts)

as much space documenting the errors than it does (should be: as it does)

few fine points that an future sed expert (should be: a future sed expert)

There’s only 63 more (should be: There are only 63 more)

some characters, like parenthesis (should be: parentheses)

this matches zero of more numbers (should be: zero or more numbers)

expand the the regular (should be: expand the regular)

leave the first world alone alone (should be: leave the first word alone)

I wrote thise. (should be: I wrote this.)

This could not done (should be: This could not be done)

can be proceeded by (should be: can be preceded by)

must wait until next section (should have a closing parenthesis)

it has it’s own (should be: it has its own)

Thank you for taking the time to help people become more proficient.

Kind regards,

Unfortunately, sed on MacOSX does not support many of the sed functionality that comes on Unix/Linux.

A more appropriate statement might be “the POSIX-specification ‘sed’ on Mac OS X has fewer features than the Gnu version of sed found on many Linux systems”.

So install a Gnu version of sed (MacPorts, Fink, roll your own)