Mike Stroyan wrote:
On Tue, Sep 22, 2009 at 02:36:30AM -0700, thahn01 wrote:
Hello, If I try something like:

$ touch a.c b.c A.c
$ ls [a-z]*.c
a.c  A.c  b.c

then I get A.c in the output, even if no capital letters are to be found.

  The "[a-z]" range expression matches characters between a and z in the
current locale's collation order.  The collation order for en_US.UTF-8 and
other locales has uppercase and lowercase alphabetic characters together.
So in those locales your range includes 'a' through 'z' and 'A' through
'Y'.  You can change the locale to "C" or "POSIX" to get plain ascii
collation order.  You can see the collation order using the sort command.

for c in {32..126}; do eval printf '"%c - %d\n"' $(printf "$'\\\\%o'" $c) 
$c;done | sort -k 1.1,1.1

for c in {32..126}; do eval printf '"%c - %d\n"' $(printf "$'\\\\%o'" $c) 
$c;done | LANG=C sort -k 1.1,1.1

The collation order lists 'a' before 'A', but actually lets a later
character break a tie between otherwise equal uppercase and lowercase
characters.  Sort will arrange 'a1', 'A1', 'a2', and 'A2' with the '1'
vs. '2' characters acting as a tiebreaker.

...and that it is why instead of using

>> $ ls [a-z]*.c

you should use

>> $ ls [[:lower:]]*.c

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