Wilcards in Linux (was: Interpretation of extensions different from Unix/Linux?)

[stefan-lucks@see-the.signature]

On Fri, 14 Aug 2009, Randy Brukardt wrote:

> "vlc" <just.another.spam.account@googlemail.com> wrote in message 
> news:8a5f3b98-1c5a-4d47-aca7-e106d1223fa9@a26g2000yqn.googlegroups.com...
> ...
> >If the specifications are different, the utilities in Ada.Directories
> >are quite unusable for UNIX/Linux.
> 
> I think you are seriously confused about how this stuff works in Unix. 
> (Either that, or I'm getting senile... ;-)

I wouldn't suggest that. I am working on a linux computer, and I thought 
you where right. But when trying out (Suse Linux 11.0), I was cought by 
suprise. 

First, the behaviour of "rm *.c":

--> start

stef@linux-3fdp:~/Post/TEST> ls -a
.  ..
stef@linux-3fdp:~/Post/TEST> touch x.c
stef@linux-3fdp:~/Post/TEST> touch y.c
stef@linux-3fdp:~/Post/TEST> touch .c
stef@linux-3fdp:~/Post/TEST> ls
x.c  y.c
stef@linux-3fdp:~/Post/TEST> ls -a
.  ..  .c  x.c  y.c
stef@linux-3fdp:~/Post/TEST> rm *.c
stef@linux-3fdp:~/Post/TEST> ls -a
.  ..  .c

<-- stop

Oops, ".c" hasn't been removed! 

Is there something special with predefined or builtin commands, such as 
"rm"? Just write a little command yourself:

--> start

with Ada.Command_Line; with Ada.Text_IO; 
use Ada;

procedure Repeat_Command is
begin
   Text_IO.Put_Line(Natural'Image(Command_Line.Argument_Count));
   for I in 1 .. Command_Line.Argument_Count loop
      Text_IO.Put_Line(Command_Line.Argument(I));
   end loop;
   Text_IO.Put_Line("----------");
end Repeat_Command;
 
<-- stop

Now, call this program with "*.c":

--> start

stef@linux-3fdp:~/Post/TEST> touch x.c
stef@linux-3fdp:~/Post/TEST> touch y.c
linux-3fdp:~/Post/TEST> ./repeat_command
 0
----------
linux-3fdp:~/Post/TEST> ./repeat_command *.c
 2
x.c
y.c
----------

<--stop

The file ".c" was still there, but the shell just called 
"repeat_command x.c y.c", ignoring the file ".c". 

I tried with different shells, including csh and sh. It was the same, 
everywhere. Apparently, "vlc" is right. 

On the other hand, I wonder where this feature has been documented -- the 
docs I found clearly defined the "*" wildcard to represent a string of any 
length, including zero. 

There appears to be a special rule if the zero-string is followed by a 
".", but where is it documented?

Just to verify that "*" _can_ represent a zero-length string:

--> start

linux-3fdp:~/Post/TEST> ./repeat_command repeat_command*
 5
repeat_command
repeat_command.adb
repeat_command.adb~
repeat_command.ali
repeat_command.o
----------

<--stop

-- 
------ Stefan Lucks   --  Bauhaus-University Weimar  --   Germany  ------
               Stefan dot Lucks at uni minus weimar dot de
------  I  love  the  taste  of  Cryptanalysis  in  the  morning!  ------