Date: Wed, 31 Aug 2005 13:42:05 -0500 From: Dan Nelson <dnelson@allantgroup.com> To: Gary Kline <kline@tao.thought.org> Cc: FreeBSD Mailing List <freebsd-questions@freebsd.org> Subject: Re: Doing a modulo in /bin/sh?? Message-ID: <20050831184205.GC16354@dan.emsphone.com> In-Reply-To: <20050831181545.GA57907@thought.org> References: <20050831181545.GA57907@thought.org>
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In the last episode (Aug 31), Gary Kline said: > I can grab the results of "w=$date+%U)"; in C an use the modulo > operator; is there a way to do this is /bin/sh? ot zsh? > > #/bin/sh > w=$(date +%U) > echo "w is $w"; > (even=$(w % 2 )); ## flubs. > echo "even is $even"; ## flubs. > > if [ $even -eq 0 ] ## flubs, obv'ly. > then > echo "week is even"; > else > echo "week is odd"; > fi For the simple even/odd case, you can AND with 1: even=$(( w & 1 )) For the general case: xmodn=$(( x - ((x / n) * n) )) which works since sh's arithmetic evaluator is integer-only. zsh has the % modulo operator, so xmod=$(( x % n )) . -- Dan Nelson dnelson@allantgroup.com
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