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Re: Number with sign is read as octal despite a leading 10#

From Chet Ramey <chet.ramey@case.edu>
Newsgroups gnu.bash.bug
Subject Re: Number with sign is read as octal despite a leading 10#
Date 2018-07-10 11:09 -0400
Message-ID <mailman.3382.1531235361.1292.bug-bash@gnu.org> (permalink)
References <CA+n9pTy7vSPUA0j-bDF9_eWF0XysePRDAFckgvvHX8haSWv7KQ@mail.gmail.com> <c8ae5df2-b6b3-438f-bd99-4618f6b2d3c0@Spark> <71850c03-54d3-6a7e-1d29-136950d9e139@iki.fi>

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On 7/10/18 6:44 AM, Ilkka Virta wrote:
> I think the problematic case here is when the number comes as input from
> some program, which might or might not print a leading sign or leading
> zeroes, but when we know that the number is, in any case, decimal.
> 
> E.g. 'date' prints leading zeroes, which is easy enough to handle:
> 
> hour=$(date +%H)
> 
> hour=${hour#0}         # remove one leading zero, or
> hour="10#$hour"        # make it base-10
> 
> The latter works even with more than one leading zero, but neither works
> with a sign. So, handling numbers like '-00159' gets a bit annoying:

That is not an integer constant. Integer constants don't begin with `-'.
Bash uses the same definition for constants as the C standard, with the
addition of the `base#value' syntax.

Since the `10#' notation is sufficient to deal with leading zeroes if you
want to force decimal, you only have to remove a leading unary plus or
minus.

-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer
		 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/

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Re: Number with sign is read as octal despite a leading 10# Chet Ramey <chet.ramey@case.edu> - 2018-07-10 11:09 -0400

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