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From: chris@mimsy.UUCP (Chris Torek)
Newsgroups: comp.unix.wizards
Subject: Re: shell and sed conflicts (was embedded NL's in shell vars)
Message-ID: <7998@mimsy.UUCP>
Date: Sun, 16-Aug-87 22:10:50 EDT
Article-I.D.: mimsy.7998
Posted: Sun Aug 16 22:10:50 1987
Date-Received: Mon, 17-Aug-87 04:43:20 EDT
References: <228@cjsa.UUCP> <25712@sun.uucp>
Organization: U of Maryland, Dept. of Computer Science, Coll. Pk., MD 20742
Lines: 39
Keywords: sed sh shell

There is no problem embedding newlines in shell variables.  The
problems people have experienced are with *evaluation* of shell
variables that *contain* newlines.  The difference is that between
putting it in and pulling it out again.  (Did you really just think
what I think you thought? :-) )  For instance:

	#! /bin/sh
	foo='bar
	baz'
	echo $foo
	echo "$foo"

produces

	bar baz
	bar
	baz

because the shell's IFS (internal field separator) set includes
newlines.  The unquoted $foo expands to two arguments.

	#! /bin/sh
	foo='bar
	baz'
	IFS=' 	'	# that is space and tab
	echo $foo

produces

	bar
	baz

because newline has been removed from the shell's field separator
set, so the unquoted $foo expands to a single argument.  Read
carefully the description of variable substitution under `man 1
sh'.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7690)
Domain:	chris@mimsy.umd.edu	Path:	seismo!mimsy!chris