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From: gwc@root.co.uk (Geoff Clare)
Newsgroups: comp.unix.questions
Subject: Using pipes within awk programs
Summary: Is it OK to do this?
Keywords: awk, pipe
Message-ID: <515@root44.co.uk>
Date: 12 Jan 88 17:41:59 GMT
Reply-To: gwc@root.co.uk
Organization: Unisoft Ltd, London, England
Lines: 26


I have discovered that it is possible to send data down a pipe from
within an awk program.  For example

	who | awk '{ print $1 | "sort" }'

gives the same output as

	who | awk '{ print $1 }' | sort

I have tried this on a whole variety of flavours of UNIX, and it
works on all of them.

My question is this:  I can't find any reference to this feature
in any of our awk manuals, so is it safe to use it? and will it
work on ALL systems or just some of them?  (I have tried it on
Uniplus+ V.2, BSD4.2, HP-UX, Sequent DYNIX, Tolerant TX).

Any awk gurus out there? (or authors?!?).

Answers to my specific question by email please, and I will summarise;
but please don't inundate my mail box with general discussions of
undocumented awk features - feel free to post those to the net.
-- 

Geoff Clare              gwc@root.co.uk            seismo!mcvax!ukc!root44!gwc