Blog entries posted in Tech Diary Entry

Minimal Matching in Vim

Brad Waite — Sun, 21 Mar 2010 19:56:47 +0100

One of the first things anyone who tackles regular expressions (regex) learns is the ".*" construct, which matches any character any number of times. What is sometimes overlooked is that the * is greedy, in that it grabs any character as many times as it can. And while that's frequently useful, there are times where you want it to grab it as few times as it can. This is called "minimal matching". For those familiar with Perl's minimal matching operator, '?', it turns oRead More...

split() function in mysql

Brad Waite — Thu, 14 Jan 2010 00:49:11 +0100

The following function definition creates a split() function that splits a string by a given delimiter and returns the specified element.

DROP FUNCTION IF EXISTS split;
CREATE FUNCTION split (str TEXT, delim VARCHAR(1), N INT)
RETURNS TEXT DETERMINISTIC
RETURN SUBSTRING(SUBSTRING_INDEX(str, delim, N), LENGTH(SUBSTRING_INDEX(str, delim, N - 1)) + LENGTH(delim) + (N > 1))

The syntax of the function is as follows.

split(str, separator, pos)

Counting characters in vim

Brad Waite — Fri, 23 Oct 2009 15:56:58 +0100

There's several ways to count the number of characters in a file within vim.

The 'n' modifier to the substitute operator ('s') tells vim only to report the number of matches, but not to actually do any substitutions. Given that, the following command will report the number of characters in our file:

:%s/.//gn

That says, "find ('s///n') every occurrence ('g') of any character ('.') in all lines ('%')." Note that this will not include any line break characters. TRead More...

dspam not checking emails

Brad Waite — Mon, 05 Oct 2009 23:05:06 +0100

I've been plagued with a recurring problem with dspam that I had been unable to track down for months. While dspam catches nearly every spam that comes into my Inbox, I noticed a pattern of email that not only weren't flagged as spam, they apparently weren't even checked by dspam; there were no X-DSPAM headers in the email.

I spent hours tracking down whether there were any qmail aliases that were dropping mail directly into users Maildirs, since that would explain what I was seeRead More...

AUser Manager

Brad Waite — Sun, 04 Oct 2009 18:52:49 +0100

AUser Manager is a fantastic component that adds much-needed security to the Joomla! user registration process. It transparently adds full-featured AJAX Captcha and RBL tests, all without any hacks or modifications to core Joomla! files.

I've attached a slightly modified version of 1.5.10 that has the following "improvements":

AUser Manager parameter options to disable the strong password generator, username available AJAX notice & password meter. They're enabled bRead More...

Vim: insert line numbers

Brad Waite — Mon, 28 Sep 2009 17:12:54 +0100

To insert line numbers at the beginning of every line in Vim, do this:

:%s/^/\=line(".")

This is a global search and replace (%s/[search]/[replace]), matching the beginning of each line (^) with an expression (\=) that returns the current line number (line(".")).

To add a comma (or any other character) after the line number, do it like this:

:%s/^/\=line(".") . ","

Any valid Vim expression is valid after the "\=", so you could start line number with 100 likeRead More...

remote syslog

Brad Waite — Sat, 26 Sep 2009 17:05:04 +0100

syslog is the standard system logging tool on most flavors of unix. It stores records of system events in a number of user-defined files. On FreeBSD, these files live by default in /var/log. syslog has a configuration file, /etc/syslog.conf, that determines which file to log system events.

What a lot of people don't know is that syslog can send events to a remote syslog server. This means you can have all of your logs from multiple machines stored on a single hoRead More...

Shutdown or Restart Vista from Remote Desktop

Brad Waite — Fri, 05 Jun 2009 06:00:00 +0100

Here's a couple of ways to do that:

Alt-F4 brings up the standard shutdown dialog.From a command prompt type: shutdown -r -t 0

Hide Desktop.ini files in Windows 7 & Vista

Brad Waite — Fri, 05 Jun 2009 06:00:00 +0100

One of the first things I do when setting up a new Windows machine is enable the option to "Show hidden files and folders" and disable the option to "Hide protected operating system files (Recommended)". You can do this in the Folder Options control panel on the View tab. Then I can see everything on my drive, even the stuff Microsoft thinks is too dangerous for me to see.

On Win 2K and XP, this works great, but in Windows 7 / Vista there's a little snag. The Desktop.Read More...

"Delete" renamed Startup folder

Brad Waite — Mon, 01 Jun 2009 06:00:00 +0100

When I was trying to troubleshoot some XP startup issues, I decided to rename the Start->Programs->Startup folder to "_Startup", thinking it would disable any startup programs.

Turns out the folder is somehow flagged as a startup folder, and no matter what it's called, the programs will still start up. In addition, Windows will create a new Startup folder. Now I've got both a "Startup" and a "_Startup" in my Programs. I can't delete Read More...

Package has no origin recorded

Brad Waite — Sat, 30 May 2009 06:00:00 +0100

After adding the HighPoint RocketRaid software package to FreeBSD, I'm now getting the following errors whenever I add or delete a package or port:

pkg_add: package hptraidconf-3.2 has no origin recorded
pkg_add: package hptsvr-3.13 has no origin recorded

The "origin" is normally the directory in the ports tree from which the package was built. However, the 3rd-party HighPoint packages aren't part of the standard FreeBSD ports tree, and so the pkg_* utilities Read More...

Create SSL Certificate Signing Request (CSR) with OpenSSL for Apache

Brad Waite — Mon, 25 May 2009 06:00:00 +0100

Overview
-------

For new SSL servers:

1. Generate new server key
2. Generate CSR
3. Have key signed
4. Install signed key

For existing SSL servers:

1. Generate CSR
2. Have key signed
3. Install signed key

Generate new server key
-----------------------

This creates a new 1024 bit server key named website.key:

# openssl genrsa -out website.key 1024
GenRead More...

Mount a Windows XP share under FreeBSD

Brad Waite — Mon, 25 May 2009 06:00:00 +0100

mount_smbfs -U -I -W ///

Example:

mount_smbfs -U fred -I fileserver -W WORKGROUP //fileserver/files /mnt

"The Windows Installer Service Could Not Be Accessed"

Brad Waite — Wed, 20 May 2009 06:00:00 +0100

After recovering from a failed XP registry software hive, my Windows Installer is reporting this error:

"The Windows Installer Service Could Not Be Accessed"

The Microsoft KB says to perform the following functions:

msiexec /unregister

msiexec /register

However, when I do that I get a "Incorrect function" error. MS says the next step is a repair installation. I'm going to play with a few things first.

"The registry cannot load the hive" - Corrupted XP registry

Brad Waite — Wed, 20 May 2009 06:00:00 +0100

I nearly toasted my XP machine today. Somehow, between installing some software, running a keygen that may have infected my machine with a virus, running a system restore and installing the latest updates, the software hive of my registry became corrupted.

On boot, I'd get a BSOD with the following error:

Stop: c0000218 {Registry File Failure} The registry cannot load the hive (file): \SystemRoot\System32\Config\SOFTWARE or its log or alternate.

Microsoft has a KRead More...

FreeBSD IPMI

Brad Waite — Tue, 05 May 2009 06:00:00 +0100

kldload ipmi or build into kernel to have local access.

To check server event log:
ipmitool sel info

To access remote IPMI server:
-I lan -H [0.0.0.0]

To print channel info for channel 6:
ipmitool channel info 6

To print lan config on channel 7:
ipmitool lan print 7

This set the authentication types on channel 7:
ipmitool lan set 7 auth CALLBACK NONE,MD2,MD5,PASSWORD
ipmitool lan set 7 auth USER NONE,MD2,MD5,PASSWORD
ipmitoRead More...

FreeBSD watchdog

Brad Waite — Tue, 05 May 2009 06:00:00 +0100

FreeBSD supports watchdog timers in the kernel. If a timer is set, and not reset or disabled within the specified time, the kernel can reboot the machine.

'watchdog -t ' starts a watchdog for n seconds. Runing watchdog(8) again in again in <n seconds, resets the timer. If 'watchdog -t 0' is run, the kernel disables the watchdog.

watchdogd(8) either runs stat(2) on /etc, or a user-defined cmd (with -e), and resets the watchdog only on a zero exit code.

Examples:

Capture smtp email from command line with tshark

Brad Waite — Thu, 30 Apr 2009 06:00:00 +0100

tshark -i em0 -f"host 127.0.0.1 and port 25" -R"smtp"

mavik Thumbnails

Brad Waite — Fri, 03 Apr 2009 06:00:00 +0100

mavik Thumbnails is a simple plugin for Joomla! that automatically creates thumbnails for any and all images in your content. Just like any other Joomla plugin, it's simple to install and configure. However, I struggled for hours to get it to work, particularly with MyBlog for use here on Tech Diary. Turns out it was working exactly like it was supposed to and I didn't know it.

Here's how to use it:

Install & enable mavik Thumbnails
Insert an image intoRead More...

CSV Improved for Joomla 1.5

Brad Waite — Sat, 21 Mar 2009 06:00:00 +0100

CSV Improved for Joomla 1.5 is the fastest and best way to quickly and easily populate your Joomla 1.5 VirtueMart store.

We're setting up several new web stores that will be selling a variety of items. VirtueMart is the most popular e-store / shopping cart component for Joomla 1.5 and I've used it a number of times in the past. After spending a few years fighting with osCommerce, VirtueMart is an absolute thrill to implement.