"Janek Schleicher" <[EMAIL PROTECTED]> writes:
> Well, yes of course I can run each filename thru all those tests, but that
>> seems kind of like a lot of huffing and puffing. I wondered if there
>> isn't something that just spits it out.
>>
>> perl `stat' does do that very thing in element[2] ($mode) but extracting
>> `type' from that number looks hideously complicated.
>>
>> Maybe running all possible tests is quicker and easier after all. It would
>> really come down to just these:
>> -f -d -l -b -c -p -S
>> But all that info is available in @elems = (stat "fname");
>>
>> Unix `stat' actually spits it out in plain english, what type it is. (at
>> least gnu `stat' does)
>
> If you write instead
> if (-f $file) {
> #
> } elsif (-d _) {
> # ^
> }
>
> Then there is no extra stat call.
> The underscore _ holds the results of the last stat call (implicitly
> called by the -f operator), so no unnecessary work needs to be done.
>
> So you gain all stat informations in equivalent access time, but with a
> much improvement in readability.
>
> (A typical statement of my programs look e.g. like
> if (-e $file && -f _ && -M > 3) { ...
> # process existing files, older than 3 days
> }
> )
I've seen that `_' crop up before
I don't understand what this means.
What `result' are we talking about here, inside _?
exit status .. TRUE or FALSE? 0 or 1 ... filename what?
$file = shift;
if(-f $file ){
print _ . "\n";
}
Results>>>
_
Further:
Won't your code try to process symlinks too?
( Maybe that is desireable though)
Or maybe symlinks are regular files. But then why is there a -l test?
consider
ls -l file*
-rw-rw-r-- 1 reader reader 5 Jun 9 16:39 file
lrwxrwxrwx 1 reader reader 5 Jun 9 16:35 file_link -> file
cat test2.pl
#!/usr/local/bin/perl -w
$file = shift;
if (-e $file && -f _ ) {
print "Perl passed <$file> as both existing
and a regular file\n=== === === ===\n";
print "Unix \`file' reports:\n" , qx( file $file);
}
Run it:
./test2.pl file_link
$ ./test2.pl file_link
Perl passed <file_link> as both existing
and a regular file
=== === === ===
Unix `file' reports:
file_link: symbolic link to file
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