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From: maart@cs.vu.nl (Maarten Litmaath)
Newsgroups: comp.unix.questions
Subject: Re: sed behaves differently when run in backquotes/subshell
Keywords: `sed`, sh, microport_system_V/AT
Message-ID: <2985@solo12.cs.vu.nl>
Date: 7 Aug 89 17:38:26 GMT
References: <350@tree.UUCP>
Organization: V.U. Informatica, Amsterdam, the Netherlands
Lines: 26

stever@tree.UUCP (Steve Rudek) writes:
\...
\GUESSES=`cat .TST | sed 's/\(.\)/\1\
\/g'|sort|paste -s -d"\0" -`

Inside backquotes escaped newlines are removed...
Now sed `sees' the following argument:

	s/\(.\)/\1/g

To protect the escaped newline:

	... | sed 's/\(.\)/\1\\

That's right: ONE extra backslash suffices - newlines are left undisturbed
inside single quotes.
In general, to debug pipe lines try something like:

	GUESSES=`cat .TST | echo sed 's/\(.\)/\1\
	/g' > /dev/tty | sort | ...`

i.e. just insert "echo" and "> /dev/tty" to see what the funny stuff expands
to.
-- 
"Mom! Eric Newton broke the day! In 24   |Maarten Litmaath @ VU Amsterdam:
  parts!" (Mike Schmitt in misc.misc)    |maart@cs.vu.nl, mcvax!botter!maart