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From: maart@cs.vu.nl (Maarten Litmaath)
Newsgroups: comp.unix.shell
Subject: Re: sh loop variable and "double indirection"
Message-ID: <8873@star.cs.vu.nl>
Date: 29 Jan 91 15:43:10 GMT
References: <1991Jan27.044258.18779@shibaya.lonestar.org> <a21801wv11X.00@amdahl.uts.amdahl.com>
Sender: news@cs.vu.nl
Reply-To: maart@cs.vu.nl (Maarten Litmaath)
Organization: VU Dept. of Computer Science, Amsterdam, The Netherlands
Lines: 48

In article <a21801wv11X.00@amdahl.uts.amdahl.com>,
	krs@uts.amdahl.com (Kris Stephens [Hail Eris!]) writes:
)In article <1991Jan27.044258.18779@shibaya.lonestar.org>
)	afc@shibaya.lonestar.org (Augustine Cano) writes:
)>I am trying to specify (at run time) an upper limit for a loop in a shell
)>script.  In pseudo-code the ideal would be something like this:
)>
)>read i
)>for 0 to i
)>do
)>...
)>done
)
)Let me give you the ksh version first, then the (slower) sh mods -- it's
)slower because each iteration requires a fork/exec not required in ksh.

Not necessarily.

	read i

	t0= rest='1 2 3 4 5 6 7 8 9'

	for h in '' $rest
	do
		for t in "$t0" $rest
		do
			for u in 0 $rest
			do
				case $h$t$u in
				999)
					echo overflow >&2
					exit 1
					;;
				$i)
					break 3
				esac
				do_something
			done
		done
		t0=0
	done

This example works for 999 iterations.  Enough?
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