Date: Fri, 21 Sep 2012 10:46:15 -0700 From: David Wolfskill <david@catwhisker.org> To: Jilles Tjoelker <jilles@stack.nl> Cc: stable@freebsd.org Subject: Re: /bin/sh arithmetic doesn't seem to like leading 0 now Message-ID: <20120921174615.GF28959@albert.catwhisker.org> In-Reply-To: <20120921173406.GC9070@stack.nl> References: <20120921170902.GC28959@albert.catwhisker.org> <20120921173406.GC9070@stack.nl>
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--5Mfx4RzfBqgnTE/w Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Sep 21, 2012 at 07:34:06PM +0200, Jilles Tjoelker wrote: > ... > > Is this intentional? >=20 > Yes, it was changed with r216547, December 2010. >=20 > This was done to avoid an inconsistency where constants starting with > "0" and containing "8" or "9" were decimal, so something like > $((018-017)) expanded to 3. Ah; OK. > There are indeed various cases where this inconsistency does not matter > (because the numbers with leading zeroes do not exceed 10). Sure. Especially when working with "month numbers". :-} > > (I can work around it -- e.g., by using sed to strip leading 0 from the > > month number (since strftime() doesn't appear to have a format that > > provides the value in a form that lacks the leading zero for values < > > 10). But I'd rather not do that if I don't need to.) >=20 > You can use date +%-m although it is not in POSIX. Ah -- I see that now ("%-* GNU libc extension....") > With POSIX only, it is still possible to do it reasonably efficiently, > for example $(( 1$(date +%m) - 100 )) or v=3D$(date +%m); v=3D${v#0}. > ... Thanks. Peace, david --=20 David H. Wolfskill david@catwhisker.org Depriving a girl or boy of an opportunity for education is evil. See http://www.catwhisker.org/~david/publickey.gpg for my public key. --5Mfx4RzfBqgnTE/w Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) iEYEARECAAYFAlBcp+cACgkQmprOCmdXAD0BiwCdFJ84BLv3FoygcebDVIWKyiMP +r8AnjfDOOYTGQMzh/y8cozAfge9nufe =vvx3 -----END PGP SIGNATURE----- --5Mfx4RzfBqgnTE/w--
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