X-Authentication-Warning:	kendall.sfbr.org: jeffw set sender to jeffw AT darwin DOT sfbr DOT org using -f
Date:	Wed, 6 Jun 2001 08:42:02 -0500
From:	JT Williams <jeffw AT darwin DOT sfbr DOT org>
To:	djgpp AT delorie DOT com
Subject:	portable equivalent to djgpp `update'
Message-ID:	<20010606084202.A18502@kendall.sfbr.org>
Mail-Followup-To:	djgpp AT delorie DOT com
Mime-Version:	1.0
User-Agent:	Mutt/1.2.5i
Reply-To:	djgpp AT delorie DOT com

I've found the djgpp utility `update' very useful in makefiles for
validating (and updating, if necessary) a local copy of some master
data file (which never changes) prior to `regression' testing:

foo.dat:	/path/to/sacred/foo.dat
		update $^ $@


What is a portable (if inefficient or inelegant) replacement for `update'?
I suppose an unconditional `cp -f' is ok, or maybe something like this
(just off the top of my head, might be insane):

foo.dat:	/path/to/sacred/foo.dat
		[ -f $@ ] && cmp -s $< $@ || cp -f $< $@
		touch $@

The `touch' updates the timestamp on the local copy in the event `cp'
might have been aliased to `cp -p'
-- 
TIA/jtw

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