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Date: Sun, 20 Feb 2011 19:37:36 -0700 (MST)
From: Warren Block <wblock@wonkity.com>
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	(wonkity.com [127.0.0.1]); Sun, 20 Feb 2011 19:37:37 -0700 (MST)
Cc: 
Subject: Re: Backtick versus $()
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Dropped the last line of the script.  Also lined up the seds to show the 
regex is the same in both.

#!/bin/sh

DESTDIR="./"
COMPFILE=".cshrc"

PSTR=`echo "${DESTDIR}${COMPFILE}" |  sed 's%\([?:.%\\]\)%\\\1%g'`
echo ${PSTR}

PSTR=$(echo "${DESTDIR}${COMPFILE}" | sed 's%\([?:.%\\]\)%\\\1%g')
echo ${PSTR}

Also, the difference is in escapes; two more backslashes added to the 
backtick version make it work:

PSTR=`echo "${DESTDIR}${COMPFILE}" |  sed 's#\([?:.%\\]\)#\\\\\1#g'`
echo ${PSTR}

Still: aren't backticks and $() supposed to be equivalent?