So I’ve been building a new security camera system. The last time I did this, I bought a Dell dual-core box, and spent about a week installing Debian, and building and rebuilding the kernel to support the dual cores, to support the BT878 video capture chipset, compile and configure motion, etc. It took a week of evenings and a weekend or two, because the Dell hardware wasn’t automatically supported, and it required special boot-time parameters to recognize the SATA controller, for example.

So I’m building a new system on a Dell Vostro 400. Right off the bat, I ran into problems with installing the Debian net-install. I was booting off a CD, but the installer couldn’t find an ATA/IDE controller for which it had a driver. Weird. This article showed me the solution to that — set the Dell controller’s SATA mode to “RAID.”

But then I hit a wall with the Intel Gigabit network controller. I couldn’t find any workarounds for it, but, after extensive Googling, found that some of the Ubuntu people may have a patch. The posting was six months old.

So screw it, thought I, and downloaded a shiny new ISO of Ubuntu 7.10 Server Edition to see whether it would work.

Damn, am I impressed! Not only did it recognize the ATA/IDE controller and the network controller, it happily recognized the BT878-based card and loaded the kernel modules. It even has motion installed as a package for easy installation. I was able to copy over all my support scripts and motion configuration files, and was up an running in less than two hours (and that includes setting up the web server, motd, special sshd tweaks, and all)!

Now, all I have to do is deal with my crisis of faith. Do I leave the Church of Debian for the radical new Ubuntuist movement?

So, in the process of organizing photographs, I wanted to examine my deeply-nested hierarchy to figure out how it’s possible I have 30,000 images (Aperture only wants me to have 10,000 in a project, so I need to re-organize the hierarchy even before I import).

So, I figured it’d be easy to use find to list all my directories, and how many images they contain. It turns out that (at least for me) it’s not.

My best stab so far is to use find and a loop, which gives me almost what I want (it not only includes the count of images in the each directory, but subdirectories as well). It fails if there are too many directories. It’s good enough. But it’s not elegant.

So CLI Deities — how would you make this pretty?

find . -type d | while read dir; do echo `ls -1 "$dir" | wc -l` $dir; done

Potential type-face issue disambiguation: after the ls, that first argument is a one, not an ell, although I suppose an ell would work too. The wc option is an ell.

As I described back in this article, I was getting segfault errors from eAccelerator.

I’m experiencing it on another, similarly-equipped GoDaddy VPS server. Same software versions, even, for Apache, PHP, eAccelerator, and OS, although this is not a old CMS Made Simple install.

Still, no good solutions out there, as far as I can google.

Here’s the clues I have found:

• The syntax function fun_name ($arg = array (blah)) is fatal.
• The order in which PHP extensions are loaded might matter.
• There are issues with files that get included or required multiple times via different paths.
• Software versions are just Too Old.

This is teh suckage.

Next thing I’ll try, when I have the time, is to upgrade the VPS to Fedora Core 6, and see if pushing those version numbers up a bit helps.

I have a number of very time consuming processes that get run by cron on various machines. Some of these processes would cause problems if they “overlapped” — e.g., a new one gets started before the old one is done.

Now, there are a lot of ways to make sure you’re unique if you’re a process, but often I don’t want to modify the source of the process to add that (for many packages, I’d rather not patch and merge and recompile every time a new version comes out). So I write a simple shell script to run the process; cron calls my shell script, and prevents the overlap.

This uses the magic of “pgrep” — unfortunately, different versions of pgrep have different flags, so the code I originally wrote (which used the “-c” flag, which counts the matching processes) didn’t port to most systems. It’s easy enough to pipe the output through a “wc -l”.

I did have to move the pgrep exec out of my if statement, though, since the comparison was going against the return code, not the output. Doh!

#!/bin/bash

RUNNING_PROCS = `pgrep -f longRunningProcess | wc -l`
if [ "$RUNNING_PROCS" -gt "0" ]
then
        echo `date` longRunningProcess still running. I\'ll let it finish. 
else
        echo `date` Starting longRunningProcess.
        /path/to/longRunningProcess -flags 
fi
echo "----------------------------"

So, I’m working on a convoluted web site, and a problem comes up. It seems that some vitally important code was not included in some pages (for the sake of argument, let’s say it’s a copyright string). This particular site has an ungodly mix of files, including .htm, .html, and .jsp files. Some of the .jsp files are actual pages, and others are stubs to be included in other .jsp pages. The majority of the full .jsp pages include a “footer.jsp” that has the desired string, so they’re good. But I need to generate a list of the full pages, of whatever sort, that lack this string.

The inverse of this problem is easy, and is the kind of thing I use all the time:
find . -name \*.htm -o -name \*.html -o -name \*.jsp -exec grep -il "myString" {} \;


Initially, I thought using the -v flag to grep would work for me, but grep -vl returns all files it sees, because -v returns the lines that match the invert expression, not the files that match the invert expression. Then there’s the problem that I need to match “full” pages rather than included .jsp stubs.

So here’s how the Mighty Power of Unix came to my rescue:

find . -name \*.htm -o -name \*.html -o -name \*.jsp | xargs grep -il "</html>" | sort -u > full_pages.txt

provides me with a list of pages that are not mere inclusions, if you accept my assumption that an inclusion won’t match the closing HTML tag.

Then I generate a list of full pages that contain the magic string and or include the footer.jsp that would contain the magic string:
find . -name \*.htm -o -name \*.html -o -name \*.jsp | xargs grep -il "</html>" | xargs grep -le "uniqueCopyrightTag\|footer\.jsp" | sort -u > pages_no_string.txt


Then I compare the files to find out which full pages lack both the magic string and the include:
comm -3 pages_no_string.txt full_pages.txt


Wow. There it is!

I bet there’s an easier way. Post an example in the comments if you know of one!

NOTE: All commands are on a single line, regardless of whether they wrap in this particular display.