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Re: Problem with Bash regex test case sensitivity
On 12/4/10, Lee Rothstein <lee@ > wrote:
> On 12/4/2010 10:06 AM, Corinna Vinschen wrote:
>
> > On Dec 4 10:05, Lee wrote:
>
> >> On 12/3/10, Eric Blake <eblake@ > wrote:
> >>> Read the FAQ. http://www.faqs.org/faqs/unix-faq/shell/bash/, E9.
>
> >> Which says the en_US locale collates the upper and lower case
> >> letters like this:
> >> AaBb...Zz
>
> >> I got that much :) What I don't get is why someone would _want_ the
> >> collating sequence to be AaBb... or why that sequence was picked for
> >> en_US instead of using the natural order of A-Za-z.
>
> > It's not the "natural" order, it's an arbitrary order which has been
> > chosen back in 1963 when the ASCII code has been defined. It's not used
> > as "natural" order outside of computer systems and it's not even the
> > natural order on some computer systems (See EBCDIC).
>
> > If you take a look into a hardcopy encyclopedia written in english,
> > you'll be very comfortable that the words are ordered lexicographically
> > instead of in ASCII coding, probably. Needless to say that ordering
> > criteria for non-english languages may contain more characters in the
> > sequence, in german for instance
>
> > "AaäBb...Ooö...Ssß...Uuü...Zz"
>
> > So, let's reiterate:
>
> > - If I need the order for the computer language, I say so:
>
> > LC_COLLATE=C.UTF-8
>
> > - Otherwise, if I need the order for the natural language, I
> > say so:
>
> > LC_COLLATE=en_US.UTF-8
> > LC_COLLATE=de_DE.UTF-8
> > ...
>
> Here's my takeaway, given Corinna's interesting and complete
> context, and my intents. (My intentions, BTW, are for my scripts
> to have as much generality as possible [given my limited skills
> ;-|].)
>
> Therefore, instead of using '[A-Z]' to represent caps, I should
> have used (?) the Posixly Correct, '[:upper:]'.
Close, you should have used '[[:upper:]]'
$ cat t_regex
#!/bin/bash
# t_regex: Test test regex
# By Lee Rothstein, 2010-12-03, 16:27:38
regex_test () {
echo -n "[A-Z] test: "
if [[ "$1" =~ [A-Z] ]] ; then
echo Contains Capital Letters: $1
else
echo Doesn\'t Contain Capital Letters: $1
fi
echo -n "[:upper:] test: "
if [[ "$1" =~ [[:upper:]] ]] ; then
echo Contains Capital Letters: $1
else
echo Doesn\'t Contain Capital Letters: $1
fi
}
unset LC_COLLATE
export LANG="C.UTF-8"
echo "=== LANG=$LANG"
regex_test dfgh
regex_test Dfgh
echo
echo
export LANG="en_US.UTF-8"
echo "=== LANG=$LANG"
regex_test dfgh
regex_test Dfgh
~/src
$ ./t_regex
=== LANG=C.UTF-8
[A-Z] test: Doesn't Contain Capital Letters: dfgh
[:upper:] test: Doesn't Contain Capital Letters: dfgh
[A-Z] test: Contains Capital Letters: Dfgh
[:upper:] test: Contains Capital Letters: Dfgh
=== LANG=en_US.UTF-8
[A-Z] test: Contains Capital Letters: dfgh
[:upper:] test: Doesn't Contain Capital Letters: dfgh
[A-Z] test: Contains Capital Letters: Dfgh
[:upper:] test: Contains Capital Letters: Dfgh
~/src
$
Lee
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