This is an updated version of my WordPress Backup Script. The new version basically does the same thing: backup up a wordpress blog (actually any site that consists of files and a MySQL database). The new thing about the script is that instead of only saving the backup locally, it also uploads it to Amazon S3.
Alpha Channel Problems When Creating .ico Files Using ImageMagick
I’ve tried to use ImageMagick to create .ico files for Open Yahtzee, out of PNGs of various sizes. The command as it should have been:
convert openyahtzee16.png openyahtzee32.png openyahtzee64.png openyahtzee.icoresulted in the alpha channel being reversed. I’ve used ImageMagick 6.4.0, and I didn’t remember this misbehavior happening in the previous versions.
While this annoyed, and was due to no apparent reason, it could be easily solved using the ImageMagick switches to reverse the alpha channel:
-channel Alpha -negateSo the command that produces a correct .ico file was:
convert openyahtzee16.png openyahtzee32.png openyahtzee64.png -channel Alpha -negate openyahtzee.icoRetrieving Google’s Cache for a Whole Website
Some time ago, as some of you noticed, the web server that hosts my blog went down. Unfortunately, some of the sites had no proper backup, so some thing had to be done in case the hard disk couldn’t be recovered. My efforts turned to Google’s cache. Google keeps a copy of the text of the web page in it’s cache, something that is usually useful when the website is temporarily unavailable. The basic idea is to retrieve a copy of all the pages of a certain site that Google has a cache of.
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Generating URL List from Access Log (access_log)
I had to parse an access_log of a website, in order to generate a sitemap. More precisely, a list of all URLs in the site. After playing around I’ve found a solution using sed, grep, sort and uniq. The good thing that each of this tools is available by default on most Linux distributions.
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NVRM: not using NVAGP, kernel was compiled with GART_IOMMU support
For the past several weeks I had a strange problem. Sometimes when I booted my computer, it would refuse to start the X server and would give the following error in dmesg:
NVRM: not using NVAGP, kernel was compiled with GART_IOMMU support!!
NVRM: failed to allocate stack!
The weird thing about it is that normally if I rebooted the computer it would magically work again. So this error only showed up once-in a while and seemed to disappear at will. Today, it happened again, so I decided to fix it.
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Understanding load average – A Practitioner Guide
The term “load average” is used in many Linux/UNIX utilities. Everybody knows that the numbers the term “load average” refers to, usually three numbers, somehow represent the load on the system’s CPU. In this post I’ll try making this three numbers clearer and understandable.
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rzip vs. bzip2 – A short comparison
I decided to benchmark rzip against bzip for my backup needs. The benchmark was performed on a 89M tar archive of a directory which I regularly backup using my Amazon S3 backup script. The directory contains mostly LaTeX, PDF and Open Office files, so this benchmark may reflect very different results than what you will get if you will test it on other kinds of files.
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usb 1-4: device descriptor read/64, error -71
When I try to connect my Sansa Clip MP3 player to the linux box I see the following error in dmesg:
usb 1-4: device descriptor read/64, error -71
and the device recognition fails. The player’s battery gets reloaded but I can’t mount it and transfer songs.
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Start Trac on Startup – Init.d Script for tracd
As part of a server move, I went on to reinstall Trac. I’ve tried to install it as FastCGI but I failed to configure the clean URLs properly. I got the clean URLs to work if the user access them, but Trac insisted on addeing trac.fcgi to the beginning of every link it generated. So I’ve decided to use the Trac standalone server, tracd.
The next problem I faced was how to start the Trac automatically upon startup. The solution was to use an init.d script for stating Trac. After some searching, I didn’t find an init.d script for tracd that were satisfactory (mostly poorly written). So I went on an wrote my own init.d script for tracd.
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Clean URLs (Permalinks) for WordPress on Lighttpd
I’ve moved my blog in the last few days to a new bigger dedicated server (as well as some other sites I own). After doing some benchmarks (I plan to post those soon) I’ve decided to switch to Lighttpd. While the exact migration notes are the topic of another post, I can say that I’m fairly satisfied with the move.
After setting up the server, I started moving the blog. Importing the files and the database was pretty straight forward. But when I thought every thing is ready and I transfered the domain to the new server I’ve found out that none of my inner pages are accessible. The reason, as it turned up pretty quickly, is that the WordPress depends on Apache’s mod_rewrite to create the clean URLs (the so called permalinks). This actually posed two problems:
- WordPress depends on Apache’s
mod_rewrite. - WordPress used
.htaccessfiles for the clean URLs configuration
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