get directory listing

[darrengan]

HI dudes, i am trying to get the folder name from a directory. I am currently using the script below to get the content of the directory:

 opendir(DIRHANDLE,"/usr/darren") || die "file to open";

 @FILES = grep !/^\.\.?$/, readdir DIRHANDLE;

 while (<@FILES>)
  {

   chop();
   $REC     = $_;
   @LINEREC = split(/\./,$REC);

  print "$REC\n";

  }

 closedir(DIRHANDLE);

By using the above method, will will get all the listing including the directory and files. how can i only show the directory in /usr/darren/?

Cheers,
Darren

[merlyn]

while (<@FILES>)

Definitely very broken code. See my previous writeup on that.

[pg]

Use -d to determine whether it is a directory. By the way, don't chop(), but chomp() if it is needed. The following code was tested on Windows XP, don't have UNIX access handy:

opendir(DIRHANDLE,"c:/") || die "file to open";
for my $file (readdir DIRHANDLE) {
    print "$file\n" if (-d "c:/$file");
}
closedir(DIRHANDLE);

[blazar]

opendir(DIRHANDLE,"/usr/darren") || die "file to open";

"file to open"?!? How 'bout $! anyway? (Check perldoc perlvar.)

Whatever, I really wonder why people insist so much in reinventing the wheel where a simple glob would do.

@FILES = grep !/^\.\.?$/, readdir DIRHANDLE;

Is '.' fine? I mean: I'm not saying it is not. Simply generally people who reinvent the wheel do throw away it too...

By using the above method, will will get all the listing including the directory and files. how can i only show the directory in /usr/darren/?

-d is your friend. Check perldoc -f -X:

my @dirs=grep -d, </usr/darren/*>;  # Whoa it's one line!!

[bluto]

Whatever, I really wonder why people insist so much in reinventing the wheel where a simple glob would do.

That's because a simple glob will get you in trouble in production code. For example...

my @dirs=grep -d, </usr/darren/*>; # Whoa it's one line!!

Yeah it's on one line and looks elegant. Unfortunately there is no error control and it skips directories with a leading '.' in the name (e.g. '.foo', '..bar'). With readdir you need to be a little careful, but it works fine. If you aren't chdir'd into the directory you are reading you generally need to prepend the directory path to each name it returns, but that's trivial.

[blazar]

Yeah it's on one line and looks elegant. Unfortunately there is no error control and it skips directories with a leading '.' in the name (e.g. '.foo', '..bar').

1. From perldoc File::Glob:

   The POSIX defined flags for bsd_glob() are:
   
   "GLOB_ERR"
       Force bsd_glob() to return an error when it encounters a directory
       it cannot open or read.  Ordinarily bsd_glob() continues to find
       matches.
   

2. Skipping directories with a leading dot may be a feature. One can glob '.*' if need be.
Not to say that there are not situations in which an explicit opendir & C. is actually preferrable. Indeed there are. My point being that in the vast majority of cases a simple glob would do instead. I think OTOH it has a stigma due to the fact that anciently it relied on a call to an external shell, which is what I read it in a book, but since I don't have effective experiennce with Perl 4, the last one that I think was set up like that, I cannot tell for sure...