Date: Fri, 25 Jun 2010 08:53:59 -1000 From: parv@pair.com To: freebsd-questions@freebsd.org, Carl Johnson <carlj@peak.org> Subject: Re: check for numeric content in a shell script (FreeBSD sh) Message-ID: <20100625185359.GA1821@holstein.holy.cow> In-Reply-To: <20100624192256.GF557@libertas.local.camdensoftware.com> References: <4C22B3D7.6070102@comclark.com> <20100624033257.2D074BEA6@kev.msw.wpafb.af.mil> <87lja4mlme.fsf@cjlinux.localnet> <87hbksmk6y.fsf@cjlinux.localnet> <87d3vgmj1s.fsf@cjlinux.localnet> <20100624183407.GA49923@holstein.holy.cow> <20100624183933.GA50443@holstein.holy.cow> <20100624192256.GF557@libertas.local.camdensoftware.com>
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in message <20100624192256.GF557@libertas.local.camdensoftware.com>, wrote Chip Camden thusly... > > On Jun 24 08:39, Parv wrote: > > in message <20100624183407.GA49923@holstein.holy.cow>, > > wrote parv@pair.com thusly... > > > > > > # Matches a number, either positive (without '+' sign) or > > > # negative, which is either a whole number; or a real number > > > # ending with decimal point, or a real number with or without > > > # leading digits before the decimal point. > > . ^ > > . ^ plural > > > ^ > > > -? > > > ( > > > [0-9] [.]? [0-9]* > > > | > > > [0-9]? [.] [0-9]+ > > . ^ > > . ^ oops > > > > Please change the immediately above regex portion to ... > > > > [0-9]* [.] [0-9]+ ... > We still need to be able to handle numbers without a decimal. First alternative above handles that ... [0-9] # Match 1 digit, [.]? # followed by an optional decimal, [0-9]* # followed by any number of optional digits. > Try this: > > [0-9]*\.?[0-9]+ If it is really /^[0-9]*\.?[0-9]+$/, then it does not match a negative number or a number ending with a decimal (e.g. 8.). > The question mark says "0 or 1" > > > > > ) > > > $ Annotated regex now is ... ^ # Anchor at the beginning of string; -? # followed by an optional -ve sign; ( # start grouping|alternatives; [0-9] # match 1 digit, [.]? # followed by an optional decimal, [0-9]* # followed by any number of optional digits; | # OR, [0-9]* # match any number of optional digits, [.] # followed by 1 decimal point, [0-9]+ # followed by 1 or more digits; ) # end of grouping; $ # anchor at the end of the string. - parv --
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