Mar 262013

I recently found an old Dunlop Crybaby Wah pedal that I’d had lying around for the past 20 years.  The thing was in horrible shape and I had forgotten I even had it, let alone used it.  Since I didn’t really have anything to lose by doing so, I ended up deciding that this might make a good project pedal to modify.  That being the case, I decided to go ahead and do the true bypass mod, which eliminates the “tonesucking” that takes place without it (high end frequencies bleed off passing through the pedal), and to add an LED indicator light as the first modification.  Here’s the story of how I did it.

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Aug 302012

Lately I’ve been spending a lot of time trying to get a useful combination of LDAP + SSL + Kerberos working on various Unix systems (Linux, Solaris, and AIX specifically).  I’ve had excellent results with Kerberos + LDAP and SSL + LDAP, but combining all three on my CentOS and RHEL systems had me running repeatedly into this error:

I first saw this when I configured my systems to authenticate against Active Directory with SSSD and then I started noticing it with the OpenLDAP clients (ldapadd, ldapmodify, et al) when I began doing more and more work using SASL/GSSAPI authentication. Continue reading »

Jan 182012

The TechRockDo yum repository has been created as a place to hold all rpm’s that I roll and use.  I’m making them available to the public; I hope you find everything you find here useful.  For now, only CentOS and RHEL 6 are supported.  There are channels for both 32- and 64-bit architectures.  To use the repository, just install the trd-release package for your architecture:

This will install the yum repository definition and the GPG key.  After that, you’ll be able to use the repository just like any other.


Dec 302011

A while back, I described a method for authenticating CentOS and RHEL servers to Active Directory using LDAP.  While this approach is easy to set up and works right out of the gate, there are a few drawbacks to it that I’ve run across:

  • Changing passwords from the Linux server does not work unless you set up LDAP over TLS/SSL, which I’ve found very difficult (though not impossible!) to accomplish
  • While changing the passwords does work, it can be very user unfriendly.  In particular error messages given are very cryptic to the lay user.  Unless you are in IT, you’re not going to know or care about the LDAP error codes that are reported back, nor are you going to want to research what the appropriate character classes are for the AD passwords so that you can choose from at least three of them appropriately.

In this article, I’ll describe how to use winbind to join your Linux server to a Microsoft Active Directory and become a domain member.

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Dec 052011
VMware Fusion Logo

Recently, I wanted to use the built-in iSight on my Mac under my Windows 7 virtual machine that I run under VMware Fusion.  I figured that the VMware Tools would have installed drivers for it, but this is not the case.  Under normal circumstances, you’d need to run Boot Camp Assistant located under /Applications/Utilities and have it download the drivers and burn them to a CD for you.  For some reason, this wasn’t working in my set up as Boot Camp Utility kept giving me an error that it couldn’t modify my disk’s partitions to work with Boot Camp properly.  That’s great, but I didn’t really want it to do anything with my partitions anyways since I’m just planning on installing the drivers and not building a separate Boot Camp install of Windows.   Continue reading »

Jul 192011
PHP Logo

A new TLF yum repository has been created for Red Hat Enterprise Linux 6-based distributions (ie CentOS 6).  As of right now, there is only a 64-bit repo.  32-bit packages are forthcoming.  php 5.3.6 packages are available here by running the following set of commands:

There are several php packages available and the above yum command is only an example if you wanted to install php, the cli, and the mysql and mbstring extensions. The extensions you need will be based upon your usage.

Jul 102011
PHP Logo

The Linux Fix yum repository has been updated with new rpm’s for the tlf-release package and for php version 5.3.6.  The new tlf-release package includes changes to the layout of the yum repository, including splitting off a separate 32-bit and 64-bit repo.  You can read the release notes for php 5.3.6 here.

You may install or update the TLF repository with the following command:

Note that this command will work on 64-bit architectures as well.  I also need to repeat the disclaimer that using any of the database extensions for this version of php will also update sqlite to version 3.6.20, which replaces some pretty core functionality of RHEL and CentOS, so please use them at your own risk.


Jul 032011

Over the past couple years, I’ve written several little php-based application that rely on LDAP for authentication.  More recently, I’ve been using CodeIgniter to write more apps.  I thought it was about time to handle LDAP authentication a little more elegantly.  To handle this, I’ve written a library for CodeIgniter called Ldap_Auth.

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May 012011

I recently got a Bluetooth Magic Mouse for my Mac Book Pro.  It’s a great piece of hardware.  I love the gesture feature, especially when browsing.  It’s pretty sweet to be able to go back a page or forward by simply swiping your fingers left or right on the top of the mouse.  In the past couple of weeks, though, the mouse has been randomly disconnecting.  It was annoying but since the MBP has a track pad built into the wrist rest, it was relatively easy to reconnect it.  Not so for those who have an iMac or Mac Pro and have to connect a USB mouse in order to reconnect.  I eventually figured out that the disconnect “feature” was reproducible any time I knocked the mouse against the side of my laptop or reached the edge of the mouse pad and had to pick up the mouse and set it down again.  It also came to my attention that if I set the mouse next to the track pad and click, it reconnects.

I ultimately found several threads detailing the same problem.  One of the proposed fixes was to jam some paper into the battery compartment.  I did so, but it wasn’t really clear to me how.  After some playing around, I found that one configuration that works is a piece of paper across the bottom of the battery compartment 3 pieces high, the batteries, then two more pieces of paper on top of the batteries, followed by the batter cover.  That seems to have cut down the number of disconnects in a most significant manner.  Now to find a real solution to this issue rather than applying a band-aid.  I’ll probably have to give a call to the Apple store.

Apr 142011

Today I was trying to help someone with a regular expression to match an e-mail address.  He was developing on a Solaris server and sent me the regular expression outlined in RFC 822 which outlines message formatting for e-mail headers.  The command he sent me to test with took a little tweaking, but I eventually came up with:

Pretty straight-forward.  Search for any alphanumeric, dot, underscore, percent sign, plus sign, or dash, repeating one or more times followed by an ‘@’ sign, then another alphanumeric, dot or dash, repeated one or more times, a dot, and then an alphabetical character repeated 2, 3, or 4 times.

The thing that gets me is that this command worked on my Mac.  It worked on a Linux server.  I sent it back to him, he tried it, and… it didn’t work.  After poking around a little bit, I determined that it was because on Solaris for this to work correctly, you need to use /usr/xpg4/bin/egrep rather than /bin/egrep, which brings me to the original reason for this post.  On Solaris, there are no fewer than four places where you may find standard OS commands – /bin, /usr/xpg4/bin, /usr/ucb, and /usr/sfw/bin.  A couple other third party distributors will also package core OS utilities (like the GNU toolset) and install them in their own directory under /opt.

Larry Ellison and His Sausage

Larry Ellison - It's his sausage, but it's not his fault.


I’d like to blame Oracle for this, but quite frankly, Sun has been doing this since I can remember with Solaris 2.5.1, which is the earliest version I’ve worked with.  I’ve been getting annoyed by this quite frequently lately, and it was finally time for me to vent.  Thank you for listening and remember, when you are on Solaris and you want to run a basic command, you must choose.  But choose wisely.  Today, with /bin/egrep, I chose… poorly.