A Unix pipe is a byte stream, not a text stream. To interpret a byte stream as text, one needs to negotiate an encoding, and Unix pipes don't offer a means to do that.
In the interest of fairness it should be mentioned that, at the time Doug McIlroy made the quoted statement, ASCII was still the text encoding of choice (at least if you were in the US). The idea that an encoding might have to be »negotiated« before a pipe could be useful didn't really show up on anyone's radar.
Also, most of the usual Unix tools assume that their input consists of lines of text separated by newline characters, rather than arbitrary »byte streams«, and generate output to suit this assumption. Note that UTF-8 was carefully defined (by Ken Thompson, no less) to fit the common Unix notion of »text« – up to a point where many Unix tools will do »reasonable« things when fed UTF-8 data even if they do not include explicit support for UTF-8.
Copyright © 2017, Eklektix, Inc.
Comments and public postings are copyrighted by their creators.
Linux is a registered trademark of Linus Torvalds