bug#24609: egrep '2\.?[0?9]' datafile does not work as expected

[Norihiro Tanaka]

On Tue, 4 Oct 2016 15:38:00 +0800
Lam Bruce <address@hidden> wrote:

> Dear Sir/Madam:
> 
>       I put all files in the atttachment.
> 
>        cat datafile
> 
> northwest NW Charles Main 3.0 .98 3 34
> western WE Sharon Gray 5.3 .97 5 23
> southwest SW Lewis Dalsass 2.7 .8 2 18
> southern SO Suan Chin 5.1 .95 4 15
> southeast SE Patricia Hemenway 4.0 .7 4 17
> eastern EA TB Savage 4.4 .84 5 20
> northeast NE AM Main Jr. 5.1 .94 3 13
> north NO Margot Weber 4.5 .89 5 9
> central CT Ann Stephens 5.7 .94 5 13
> 989
> 
> egrep '2\.?[0?9]' datafile
> eastern EA TB Savage 4.4 .84 5 20
> 
> egrep '2\.{0,1}[0?9]' datafile
> eastern EA TB Savage 4.4 .84 5 20
> 
> egrep '2\.\{0,1\}[0?9]' datafile
> 
> egrep '2\.{0,1}[0-9]' datafile
> western WE Sharon Gray 5.3 .97 5 23
> southwest SW Lewis Dalsass 2.7 .8 2 18
> eastern EA TB Savage 4.4 .84 5 20
> 
> egrep -n '2\.{0,1}[0-9]' datafile
> 2:western WE Sharon Gray 5.3 .97 5 23
> 3:southwest SW Lewis Dalsass 2.7 .8 2 18
> 6:eastern EA TB Savage 4.4 .84 5 20
> 
> Best Regards,
> 
> Bruce

EN DASH (U2013) instead of HYPHEN-MINUS (U002D) are used in from first
to third question.

[0 U2013 9] does not express a range to a list of 0, U2013 or 9, so I
seem that all results are right.