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Hacker Public Radio

Your ideas, projects, opinions - podcasted.

New episodes Monday through Friday.

Call for shows

We are running very low on shows at the moment. Have a look at the hosts page and if you don't see "2014-??-??" next to your name, or if your name is not listed, you might consider sending us in something.

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The 4th Annual HPR New Year 26 hour show

Yes it't that time of year when HPR opens it's hands and welcomes all the Tech podcast community to gather and chat. Meet old friends and make a few new ones. This is the 4th Annual show that is streamed live and then podcasted via the Hacker Public Radio feed. While it is enabled by HPR Volunteers, it is put on for the benefit of the FLOSS, Tech, Security podcast community in general.

We would kindly ask as many people as possible to spread the word

  • Starting:
    • 10 in the morning New Years eve, UTC, 2014-12-31T10:00:00Z
  • Ending:
    • Noon New Years Day UTC, 2015-01-01T12:00:00Z
  • Latest Shows

    hpr1649 :: Raspberry Pi Accessibility Breakthrough

    How I fixed the stuttering text-to-speech on a Raspberry Pi

    Hosted by Mike Ray on 2014-11-27 and released under a CC-BY-SA license.
    Listen in ogg, spx, or mp3 format. Comments (0)

    Since April last year the text-to-speech using eSpeak in the Raspberry Pi console has stuttered very badly and regularly crashes the kernel.

    Here's how I fixed it.

    Cloning my github repo:

    git clone


    cd ttsprojects/raspberry-pi/libilctts/build
    sudo ./
    cd ../../piespeakup
    sudo ./

    Bingo! Speech should work.

    This has only just been released and there is still work to do on the documentation.

    Note: I am not connected to the Raspberry Pi Foundation in any way and anything I say or do is not endorsed by them.

    My email address is connected with a Freelists email list I set up and an accompanying web site:

    The 'VI' is for 'Visually Impaired' and I DID check with the Foundation about the similarity of the web address before I created it.

    To join our email list send an email to:

    With 'subscribe' in the subject.


    hpr1648 :: Bash parameter manipulation

    A summary and aide memoire of Bash parameter expansion methods

    Hosted by Dave Morriss on 2014-11-26 and released under a CC-BY-SA license.
    Listen in ogg, spx, or mp3 format. Series: Bash Scripting | Comments (0)

    Bash parameter manipulation

    I'm a great fan of using the Linux command line and enjoy writing shell scripts using the Bash shell.

    • BASH (or more usually Bash or bash) is the name of a Unix shell. The name stands for Bourne Again SHell, which is a play on words. Bash is an extension of the shell originally written by Stephen Bourne in 1978, usually known as SH.

    • Bash was written as part of the GNU Project which forms part of the Linux Operating System.

    • A shell is the part of the operating system that interprets commands, more commonly known as the command line.

    • A knowledge of Bash is very helpful if you would like to be able to use the power of the command line. It is also the way to learn how to build Bash scripts for automating the tasks you need to perform.

    In this episode we look at what parameters are in Bash, and how they can be created and manipulated. There are many features in Bash that you can use to do this, but they are not easy to find.

    As I was learning my way around Bash it took me a while to find these. Once I had found them I wanted to make a "cheat sheet" I could stick on the wall to remind me how to do things. I am sharing the result of this process with you.

    The version of Bash which I used for this episode is 4.3.30(1)-release

    The full notes for this episode are to be found here:

    hpr1647 :: Oggcast Planet Live 2014: The Cooking Show

    OggCast 2014. we cook dinner, I drink beer, a time is had by all.

    Hosted by FiftyOneFifty on 2014-11-25 and released under a CC-BY-SA license.
    Listen in ogg, spx, or mp3 format. Comments (0)

    OggCast 2014. we cook dinner, I drink beer, a time is had by all. I'd like to amp this, but Audacity won't let me, so listen carefully.

    Broam, Briptastic, and FiftyOneFifty talk about the meal they are making for Saturday Night at Oggcast Planet Live 2014 from when they thought about it until dinner was served, as well as that day's fun at Knoebels theme park at Elysburg PA and the plans to visit the ghost town of Centralia the following day.

    hpr1646 :: 5150 Shades of Beer 0003 River City Brewing Company and Wichita Brewing Company

    FiftyOneFifty explores Wichita Brew Pubs, v2

    Hosted by FiftyOneFifty on 2014-11-24 and released under a CC-BY-SA license.
    Listen in ogg, spx, or mp3 format. Series: 5150 Shades of Beer | Comments (0)

    Image of beer


    hpr1645 :: 42 - LibreOffice Calc - Data Manipulation 2: Standard and Advanced Filters

    A look at the more advanced filtering options for manipulating data in Calc.

    Hosted by Ahuka on 2014-11-21 and released under a CC-BY-SA license.
    Listen in ogg, spx, or mp3 format. Series: LibreOffice | Comments (0)

    You can set a Standard Filter from within the AutoFilter drop-down, or you can go there through the Data menu by selecting Data>Filter>Standard Filter. Now lets look at the question we ended the last tutorial with: How many females over the age 40 had a case in 1978. We saw we could get this by manually putting checkmarks in every age that was greater than 40 using AutoFilter, but how do we do this using Standard Filter? - For more go to

    hpr1644 :: Benetech, OpenStack and Kumusha

    Benetech CEO opens up, the challenge of OpenStack product management, and Kumusha Takes Wiki.

    Hosted by semioticrobotic on 2014-11-20 and released under a CC-BY-SA license.
    Listen in ogg, spx, or mp3 format. Series: NewsCast | Comments (0)

    In this episode

    Open source product development most effective when social

    Benetech started out in the 90s without even understanding the meaning of the term open source. They just "needed an easy way to interface with different voice synthesizers" to develop readers for people who are blind and "shared the code to be helpful."

    Sound familiar? started covering stories like in 2010 and they recur more often than you might think. Stories of people sharing the code to help others—but sharing code to get help developing better code. When code is open, a community has the opportunity to form around it.

    Read this interview about what Benetech CEO Jim Fruchterman learned by adopting open source philosophy and furthering technology-for-good.
    Read more:

    OpenStack product management: wisdom or folly?

    Two recent, excellent, blog posts have touched on a topic I've been wrestling with since May's OpenStack Summit: What is the role of the Product Management function, if any, in the OpenStack development process?

    The first article, "Calling all 'User Landians' to lead OpenStack above the cloud," by Evan Scheessele, talks about the "real user" of OpenStack—those people that need to deliver a solution that brings some sort of value to their organization. The other article, "Who's In Charge Here Anyway?…," by Rob Hirschfeld, speaks to the dynamics of how decisions—which OpenStack features are in in or out—get made in the OpenStack ecosystem.
    Read more:

    Giving Sub-Saharan African communities an online presence

    People in Sub-Saharan Africa face hurdles to get online. Despite some progress, the region lags behind in Internet connectivity due to the high costs of service and poor infrastructure, according to a recent World Economic Forum report.

    This digital divide means some African communities are underrepresented on the web. Without a well-developed online presence, misinformation about them can spread relatively unchallenged.
    Read more:

    hpr1643 :: Unison Syncing Utility

    Review of the Unison graphical Syncing Utility

    Hosted by FiftyOneFifty on 2014-11-19 and released under a CC-BY-SA license.
    Listen in ogg, spx, or mp3 format. Comments (2)

    Unison is a file syncing/backup utility, similar to SyncBack on Windows, available in most repros.

    1. The graphical interface requires the installation of unison, and unison-gtk.. Unison may be installed w/o the graphical component, but all operations must be initiated from a system running the GUI.
      • Network backups require RSH or SSH to be installed on both machines
    2. The standard wisdom seems to be the rsync does not do a true 2 way sync, i.e., to sync to the newest file version going both ways you would have to do rsync ~/LocalFolder you@server:/home/you/RemoteFolder then turn around and do rsync you@server:/home/you/RemoteFolder ~/LocalFolder. Add that to the fact that like cp, or scp, rsync requires separate commands for files with extensions, files without, and hidden files, creating a bash script for syncing files is more complex than creating a Unison profile.
    3. Step One: If, like me you are syncing only Documents, make your subfolder structure the same on both machines, ergo, if one PC has /home/you/Documents/recipe and second PC has /home/you/Documents/Recipes, edit your folder structure to be the same on both PCs to avoid duplicate files and folders
    4. Launch Unison and create a backup profile First use, create a profile
      • Name of profile
      • Synchronization kind (Local, SSH, RSH, TCP)
      • "First" Directory (you can browse your mounted volumes)
      • "Second" Directory, if you chose Local
      • Host Machine Name (or IP Address)
      • User Name (If you haven't registered SSH keys, you will be prompted for a password on every synchronization.
      • Check whether you want to use compression, (on fast networks or slow processors, compression may create more overhead than it's worth).
      • Target directory (If it's on a remote server, you will need to type the full path, there is no browsing to the folder.)
      • Tell Unison if either folder uses FAT (say an un-reformatted USB stick)
      • If you are backing up to another system, Unison needs to be installed on both. If you are backing up to a server with no GUI desktop manager, you can install just the unison package without unison-gtk, but all the syncs will have to be initiated from the machine with a GUI. (Of course, if you back up to a remote volume that is mounted locally, it should be completely transparent to Unison). If you choose to sync via ssh (recommended), you will need ssh and ssh-server installed appropriately on each machine.
    5. Select and run your profile.
      • The first time, expect to get a warning that no archive files (index files that speed up the synchronization scan) were found. They will be created on the first sync.
      • Unison will look for differences between the files in the two selected directories. The differences will be displayed graphically, with arrows pointing left or right, indicating which directory contains the most current version of the file (by modification date). You can choose to merge files either left or right (a conventional backup), do a merge (i.e., Unison itself decides how to combine data from files with the same name (obviously, that could be messy), or to do a sync (ergo, the most current version of a file overwrites older version, regardless of location). Click "Go" to do a true sync.

    hpr1642 :: Frist Time at Oggcamp

    Join Al and Jerry where we discuss are first visit to oggcamp

    Hosted by Al on 2014-11-18 and released under a CC-BY-SA license.
    Listen in ogg, spx, or mp3 format. Series: OggCamp | Comments (1)

    This episode is about how Al and Jerry Meet at Oggcamp. What we enjoy about the event,what to expect and encourage people to attend next year.

    This is my second HPR episode after beni recorded a interview with me at oggcamp and said I should submit my own episode


    hpr1641 :: The real reasons for using Linux

    The real reasons for using Linux

    Hosted by johanv on 2014-11-17 and released under a CC-BY-SA license.
    Listen in ogg, spx, or mp3 format. Comments (1)

    I am a Linux user since the end of 1999. Which is 15 years already. I've also been trying for almost 15 years to convince other people to try Linux. And I must confess that I very often used wrong arguments doing this. After 15 years it is time to ditch some fake arguments, and to tell you the real reasons why you should switch to Linux. :-)

    I apology for the bad audio quality. A full transcript of this episode can be found on my blog.

    hpr1640 :: Symmetric vs. Asymmetric Encryption

    This episode looks the two kinds of encryption keys, and why to use each one.

    Hosted by Ahuka on 2014-11-14 and released under a CC-BY-SA license.
    Listen in ogg, spx, or mp3 format. Series: Privacy and Security | Comments (2)

    Previously we looked at Public Key encryption, which is also called Asymmetric Encryption because it uses two different keys for the encryption and decryption. This allows us to solve one of the biggest problems in secure encrypted communication, which is key distribution. Because the public key can be freely distributed, you dont need to maintain security around the process of distributing keys. Symmetric encryption, on the other hand, relies on a shared key that is used for both encryption and decryption. An example of this is the one-time pad, where you printed up a pad of paper that contained various keys, and each one was used only once. As long as no one can get the key, it is unbreakable, but the big weakness was key distribution. How do you get the one-time pad into the hands of your correspondent? And you would need to do this with separate one-time pads for each person you needed to communicate with. These are the kinds of problems that made asymmetric encryption so popular. Finally, symmetric key crypto cannot be used to reliably create a digital signature. The reason should be clear. If I have the same secret key you used to sign a message, I can alter the message, use the shared secret key myself, and claim you sent it. - For more go to