Tutorial Addendum on Perl - Allotment A - Account Agenda Entries

Displaying Agenda Timberline - DirTree.pl

    

Both Unix and Windows systems adapt book directories into a timberline structure.

    

The afterward program. DirTree.pl, shows you how to bisect the agenda tree,

    

and affectation agenda entries:

    

 

    
#- DirTree.pl

    
#- Absorb (c) 1995 by Dr.  Yang

    
#

    
   ($dir) = @ARGV;

    
   $dir = "." unless $dir;

    
   &loopDir($dir, "");

    
   exit;

    
sub loopDir {

    
   local($dir, $margin) = @_;

    
   chdir($dir) || die "Cannot chdir to $dir

";

    
   local(*DIR);

    
   opendir(DIR, ".");

    
   while ($f=readdir(DIR)) {

    
      next if ($f eq "." || $f eq "..");

    
      book "$margin$f

";

    
      if (-d $f) {

    
         &loopDir($f,$margin."   ");

    
      }

    
   }

    
   closedir(DIR);

    
   chdir("..");

    
}

    

Be careful, don t try this program in the basis directory. It will aftermath

    

a actual actual continued account of files and directories. I approved it on the working

    

directory area I stored my Perl addendum and programs, and I got the following:

    

 

    
>DirTree.pl ..

    
htm

    
   about.html

    
   active_perl.html

    
   book.css

    
   book_fo.xsl

    
   dot.gif

    
   help.html

    
   open.html

    
   opendir.html

    
   reference.html

    
   toc.html

    
   ...

    
src

    
   DirTree.pl

    
   hello.pl

    
   hello.prg

    
   opendir.pl

    
   ...

    

If you analysis DirTree.pl, you will see some absorbing statements and techniques:

    

    
• " $dir = "." unless $dir;" is acclimated to accept a absence directory, if annihilation
  
      

  specified on the command line.
  
      



    
• " local($dir, $margin) = @_;" is acclimated to create $dir and $margin as bounded variables.
  
      

  This actual important, back loopDir() is alleged recursively.
  
      



    
• " local(*DIR);" is acclimated to create DIR as bounded capricious in any name spaces,
  
      

  including agenda handle name space. In fact, this is the alone way to create
  
      

  directory handle names local.
  
      



    
• " if (-d $f) {" is acclimated to analysis the agenda access to see if it is a
  
      

  directory.
  
      



    

Counting Files - DirCount.pl

    

My additional of archetype of traversing agenda timberline is DirStats.pl. It collects several

    

statistics of the defined agenda tree:

    

 

    
#- DirCount.pl

    
#- Absorb (c) 1995 by Dr.  Yang

    
#

    
   ($dir, $extension) = @ARGV;

    
   $dir = "." unless $dir;

    
   $extension = "pl" unless $extension;

    
   $dirCount = 0;

    
   $fileCount = 0;

    
   $fileSize = 0;

    
   $otherCount = 0;

    
   $otherSize = 0;

    
   &loopDir($dir);

    
   book "Number of directories = $dirCount

";

    
   book "Number of files with .$extension = $fileCount

";

    
   book "Total admeasurement of files with .$extension = $fileSize

";

    
   book "Number of additional files = $otherCount

";

    
   book "Total admeasurement of additional files = $otherSize

";

    
   exit;

    
sub loopDir {

    
   local($dir) = @_;

    
   chdir($dir) || die "Cannot chdir to $dir

";

    
   $dirCount++;

    
   local(*DIR);

    
   opendir(DIR, ".");

    
   while ($f=readdir(DIR)) {

    
      next if ($f eq "." || $f eq "..");

    
      if (-d $f) {

    
         &loopDir($f,);

    
      } elsif ($f=~/.$extension$/) {

    
         $fileCount++;

    
         $fileSize += -s $f;

    
      } abroad {

    
         $otherCount++;

    
         $otherSize += -s $f;

    
      }

    
   }

    
   closedir(DIR);

    
   chdir("..");

    
}

    

The first run is on my Perl addendum alive directory. The achievement shows that I have

    

5 Perl files in 5 directories with absolute admeasurement of 8437 bytes. And there are some

    

other files in these directories:

    

 

    
>DirCount.pl ..

    
Number of directories = 5

    
Number of files with .pl = 5

    
Total admeasurement of files with .pl = 8437

    
Number of additional files = 44

    
Total admeasurement of additional files = 115580

    

Then I run my DirCount.pl on the Windows arrangement agenda to calculation how some executable

    

files do we accept the system:

    

 

    
>DirCount.pl c:winnt exe

    
Number of directories = 353

    
Number of files with .exe = 975

    
Total admeasurement of files with .exe = 111390120

    
Number of additional files = 10218

    
Total admeasurement of additional files = 1376214106