Everyone who uses SVN knows that most repositories are set up to allow viewing of their contents via a web browser. For example, here's the trunk of WP Plugins SVN: http://plugins.svn.wordpress.org/ and here is the current trunk version of a specific file, let's say http://plugins.svn.wordpress.org/stats/trunk/readme.txt.

The Problem

However, what if you wanted to view a specific revision of a file or directory in your browser?

Let's say I wanted revision 100,000 of http://plugins.svn.wordpress.org/stats/trunk/readme.txt

Normally, on a command line, you'd do something like

svn co http://plugins.svn.wordpress.org/stats/trunk/readme.txt stats
cd stats;
svn up -r100000 readme.txt

or simply

svn export -r100000 http://plugins.svn.wordpress.org/stats/trunk/readme.txt

However, how would you do this in your browser? Trying something like ?r=100000 or ?revision=100000 parameters doesn't work.

The Solution

Here is the syntax to get a specific revision of a file or directory:

1. Take the root of the repository (in our case, http://plugins.svn.wordpress.org)
2. Append this string !svn/bc/REVISION_NUMBER right after the repository root and before the directory or file path.

Going back to our example:

• http://plugins.svn.wordpress.org/!svn/bc/100000/stats/

  shows the stats directory exactly as it was at revision 100,000 and

• http://plugins.svn.wordpress.org/!svn/bc/100000/stats/trunk/readme.txt

  shows our readme.txt at 100,000.

And that's how you do it, folks. Happy revisioning!

Update: this post is now sponsored by Wirefly Learn where you can find cell phone news and reviews, as well as comparisons and videos.

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Let me briefly discuss some of the other methods first.

Limited

Using glob() (or <>, TODO verify) you can find files in a single directory, using only the limited shell wildcard support. For example,

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my @files = glob("tmp*");

Boring

File::Find is the de facto standard for searching in Perl.

This method finds files that end in .pl in "." and "../SomeDir", following symlinks:

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#!/usr/bin/perl -w
 
use File::Find;
use Data::Dumper;
use File::Basename;
my @directories_to_search = (".", "../SomeDir");
my @file_list = ();
 
find(
  { wanted =>
    sub {
      if ( basename($File::Find::name) =~ /\.pl$/i )
      {
        push @file_list, $File::Find::name;
      }
    },
    follow => 1
  },
  @directories_to_search
);
print Dumper @file_list;

It works fine, except it's horribly ugly and boring. Let's have a look at something more fun.

The Fun And Elegant Way

File::Find::Rule. Just have a look at this beauty.

Just like above, find all .pl files in "." and "../SomeDir", following symlinks:

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print Dumper (File::Find::Rule->name("*.pl")->file->extras({ follow => 1 })->
in(".", "../SomeDir"));

Same as above, except bypass .svn directories (shaves off a ton of time with a lot of directories):

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print Dumper (File::Find::Rule->not(File::Find::Rule->directory->name('.svn')->
prune->discard)->name("*.pl")->file->extras({ follow => 1 })->in(".", "../SomeDir"));

Find all .log files that are older than 24 hours in "."

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my $epoch_time_1_day_ago = time() - 60*60*24;
print Dumper (File::Find::Rule->file->name("*.log")->
mtime("<$epoch_time_1_day_ago")->in('.'));

Be sure to read the File::Find::Rule perldoc for more options and remember: have fun with your code!

Thanks to Perlbuzz and Andy Lester for pointing me to this library a few months ago.

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tar -tzf file.tar.gz

-t: lists files
-f: instructs tar to deal with the following filename (file.tar.gz)
-z: informs tar that the it's dealing with a gzip file (-j if it's bzip2)

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#!/usr/bin/perl -w
use strict;
my $name = "some_file.flv"; # or http://example.com/file.mp4?foo=bar
my $is_media_type = ($name =~ /\.(wmv|avi|flv|mov|mkv|mp..?|swf|ra.?|rm|as.|m4[av]|smi.?)\b/i);
if($is_media_type){
  print "media extension found\n";
}
else{
  print "not a media file\n";
}

This gets the job done without triggering any false positives (at least for the files/urls I've been dealing with so far). Am I missing any obvious types? Do you have a better way to accomplish the same thing? If so, please share in the comments.

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