I remember when I fell in love with Perl. It was the summer of 1995, and peliom and I had just met, and were working at the Lab. Postscript hacking using MacPerl on OS 8. It was beautiful.

That was more than ten years ago, and even though I’ve remained a Perl hacker the whole time, I see massive amounts of development happening on Python and Ruby, and the Perl community seems to be slowing down (what’s up with Perl 6 anyway?), so, despite the lack of block-level scope, I think it might finally be time to move on.

I don’t know enough about either Python or Ruby to figure out which to learn, so I’ll learn them both, and deal with choosing one later. Along the way I’ll post some example scripts. Anyone else making the jump from Perl or PHP to something modern might find these useful. Here is the first example: printing out a directory listing using readdir and glob in your favorite scripting language:

[perl]

1. !/usr/bin/perl
   

use strict;
use warnings;

my $dir = ‘/’;

1. Use readdir
2. _______________________________________________________________________________
   

print “Directory listing in perl of $dir using readdir\n”;
opendir(HANDLE, $dir) or die “Cannot opendir $dir: $!”;
foreach my $file (readdir(HANDLE)) {
print “\t$file\n”;
}
closedir(HANDLE);

1. Use globbing
2. _______________________________________________________________________________
   

print “Directory listing in perl of $dir using globbing\n”;
foreach my $file (glob(“/*”)) {
print “\t$file\n”;
}
[/perl]

[python]

1. !/usr/bin/python
   

import os
import dircache
import glob

dir = “/”

1. Use os.listdir
2. _______________________________________________________________________________
   

print “Directory listing in python of ” + dir + ” using os.listdir”
files = os.listdir(dir)
for file in files:
print “\t” + file

1. Use dircache
2. _______________________________________________________________________________
   

print “Directory listing in python of ” + dir + ” using dircache”
files = dircache.listdir(dir)
for file in files:
print “\t” + file

1. Use glob
2. _______________________________________________________________________________
   

print “Directory listing in python of ” + dir + ” using glob”
files = glob.glob(“/*”)
for file in files:
print “\t” + file
[/python]

[ruby]

1. !/usr/bin/ruby
   

dir = “/”

1. Use foreach
2. _______________________________________________________________________________
   

print “Directory listing in ruby of #{dir} using Dir.foreach\n”
Dir.foreach(dir) {|file| print “\t#{file}\n” }

1. Use glob
2. _______________________________________________________________________________
   

print “Directory listing in ruby of #{dir} using Dir.glob\n”
files = Dir.glob(“/*”)
files.each do |file| print “\t#{file}\n” end
[/ruby]

These scripts, as well as a PHP version, are checked in at SourceForge.

Filed under: code code, example scripts, perl, php, python, ruby · 3 Comments