We've covered Tor in LJ before (see Kyle Rankin's “Browse the Web without a Trace”, January 2008), but that was some time ago, and this subject seems to be more timely with each passing day. Also, with Tor being at only 0.2.x status, it still qualifies as software in development, so I'm justified in featuring it this month.

For those not in the know, Tor stands for The Onion Router, and its roots go all the way back to the US Naval Research Laboratory, Tor's original sponsors. It then became an EFF (Electronic Frontier Foundation) project until 2005, and it now has moved up to being its own nonprofit research/education organization: the Tor Project.

The essential idea is that your original IP address is masked by passing it through numerous special routers, designed to avoid keeping records, until the original source has been lost and the receiving end knows only about the last Tor box it encounters. To quote Tor's man page:

However, all that may be a bit headache-inducing, and the Tor Web site explains things in human terms quite nicely:

Tor takes a clever approach to anonymity, deliberately losing IP addresses as it bounces from server to server.

Tor can be a bit hard to understand at first, but if you look around, many tools can help you along the way, such as TorK and even custom distributions built around using Tor.

Installation and Usage

Surprisingly, there aren't many strange library requirements for Tor; it may install straightaway on many systems. The only missing library that got in the way was libevent, and installing libevent-dev (which selects the other needed libevent libraries along with it at the time) sorted this out. However, Tor recommends using the program Polipo, but I'll get to that in a moment.

To install Tor, head to the download page where source and binaries are available. You can figure out the binaries yourself, but for those using source, grab the latest tarball, extract it, and open a terminal in the new folder. Enter the usual commands:

$ ./configure
$ make

If your distro uses sudo:

$ sudo make install

If your distro doesn't:

$ su
# make install

To set up Tor for Web browsing, at this point, you have to install Polipo. This is in most distros' repositories, so you can decide how you want to install Polipo yourself. I'll quote Tor's documentation from here:

It's really hard to do justice to Tor in this small space, so I hope I've at least pointed you in a useful direction and haven't made any glaring errors. It really is worth heading to the Web site to understand it more fully. Speaking of the Web site, here's an appeal from the Tor folks themselves:

Information is becoming increasingly unsafe, and certain governments and corporations are becoming increasingly invasive regarding personal data. It's time that Net users started taking more care with their information, and Tor is an interesting technology that I'm sure will continue to become more relevant over time.

I love niche programs, especially in the area of multimedia. If you're like me, you probably have a folder full of MP3s and Oggs collected from the last ten years that's reached the point where you've forgotten half the files in there. This month, I stumbled upon the charming little command-line program, audiopreview. To quote the project's Freshmeat entry:

audiopreview is a simple and easy command-line program for previewing large numbers of music files.

Although the name may suggest otherwise, audiopreview also plays video files.

Installation

Packages for audiopreview are available in Debian/Ubuntu format or the usual source. If you're running with the source, according to the man page, you need the following libraries: gstreamer0.10-plugins-base, gstreamer0.10-plugins-good, gstreamer0.10-plugins-bad and gstreamer0.10-plugins-ugly.

I found I also had to install the intltool library to get past the configure script. Once you have the library side of things sorted out, compile the program with the usual:

$ ./configure
$ make

If your distro uses sudo:

$ sudo make install

If your distro doesn't:

$ su
# make install

Usage

Using the actual command can be as simple as entering the folder where the files you want to hear are located and entering:

$ audiopreview *

(The * is used to indicate all the files in a folder.)

Once the program is running, you'll be greeted with a simple track listing, along with other relevant information in purple. As far as controls go, the spacebar pauses and unpauses the stream, N plays the next stream, and P plays the previous stream. R restarts the current stream, and Q stops playing and exits the program.

That's the basic usage out of the way, but let's refine it with some command-line switches to hone your usage. For new Linux users, these are added at the end of the command, like this:

$ audiopreview files-to-play --switch

If you plan on using audiopreview to play a whole song instead of in segments, use the switch --entirely or -e.

If you want audiopreview to start over again after the last song has been played, use --loop or -l.

As mentioned previously, audiopreview also can play some video formats. However, this being a command-line program, there's a good chance you may not have X running. If so, you'll want to disable the video to avoid errors. To do so, enter --no-video.

The default starting position for each file seems to be random, which might become annoying for those looking for more specific sections of a song. Thankfully, you can specify which section of a song you want to hear with a simple numerical switch. Add: --position=POSITION or -p POSITION, and replace POSITION with the numbers 0, 1, 2 or 3. 0 sets the position to the beginning, 1 to the middle, 2 to the end, and 3 makes the start position random.

Last but not least, engage the all-important shuffle function with --shuffle or -S. For example:

$ audiopreview *.mp3 -p 1 --shuffle

The above command plays all the MP3 files in a directory, sets the starting position to the middle of a song and shuffles the order in which they're played.

You can work out the rest from here, but honestly, do yourself a favor and check out the man page with:

$ man audiopreview

Ultimately, audiopreview fills a nice little niche that will appeal to anyone sorting through large collections of music (and some video) files. DJs in particular will find this of real use, but I found it great for rediscovering songs I hadn't listened to in years. Love it.