Posts Tagged "linux"

sietchtabr reboot

I have a VM slice that I use to run DNS, a bzflag server, and a few other incidental things. This is what I see on it right now:

% uptime
12:05:13 up 450 days, 15:17,  5 users,  load average: 1.93, 1.35, 0.60

It's currently running Debian lenny, but I decided that I wanted to get with the times and upgrade it to squeeze. As expected the upgrade was fairly painless (took me a bit to figure out that booting by label was broken and I needed to boot by disk UUID), but it's kind …

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Linix Tip of the Day: SystemTap

The other day, one of my co-workers, Evan, presented an interesting problem to me. Every day, at some point, a file named ] gets created in his home directory. He assumes that it is being created by a script with a typo in it… somewhere. But how to find out? It's a hard thing to grep for.

My initial solution was to use inotify (which you might remember from a previous post) combined with libnotify to alert him if it happens while he was at his computer. It looked like the following:

$ inotifywait -t 0 --exclude='.*[^]]$' $HOME && notify-send "something just created …
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*nix Tip of the Day: Waiting in Scripts

Scripting is what makes Unix-like operating systems great. Every *nix, be it Linux, BSD, OS X, AIX, Solaris, or whatever other random distribution you can come up with, comes with a capable shell (or three) and a good set of basic utilities. Where a Windows administrator has to either fall to the horror that is Batch files, write code in a big, heavy programming language language, or submit to the terrible dominance of “management utilities”, a Unix system administrator has tons of the tools at his disposal to fix and automate things. I could talk about scripting forever (it is a substantial portion of my job), but today I'm just going to talk about one small facet: waiting for things to happen.

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Dynamic DNS: Part Two

Bonjour This post is a follow-up to Dynamic DNS

When last I left you, we had basic updateable DNS running and could update it from OS X. I've been a bit busy since then, but thanks to some prodding from @Loredo, I got back in and started looking at. What follows is the exciting story of how I got things up and running – by the end of this post, you'll have access to a working copy of dnsextd for linux, and a client application that updates SRV and IP (A/AAAA) leases. Woo.

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SpamAssassin 2010 Bug

Hey all. One of the sysadmins at Mudd, Claire Connelly, pointed out that there's a widespread bug in SpamAssassin that might cause large numbers of false positives on mail sent after 2010-01-01. Apparently, the "date in future" rule is hardcoded to look for years after 2010. You can read more at LWN; the short of it is that you probably want to add the following to your SpamAssassin config:

score FH_DATE_PAST_20XX 0.0

sa-update may or may not be pulling down updated rules. You can find the relevant bug at the SpamAssassin Bugzilla (#5852). Anyhow, something fun to be aware …

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*nix Tip of the Day: VMS

Okay, so this is maybe a little unusual, but today's "*nix Tip of the Day" isn't about Unix/Linux/etc. at all. Instead, it is about their antiquated archenemy: VMS. First, a little bit of history:


Way back in 1970, the PDP-11 was hot stuff. Ken Thompson, Dennis Richie, Brian Kernighan, and others at Bell Labs were writing what would become Unix for the PDP-11 (well, for the PDP-7 at first, but nobody talks about that). Unix was a huge improvement over what DEC shipped with the PDP-11, DOS-11 and RT-11. This couldn't stand, so Dave Cutler at DEC designed VMS. It was a new operating system, with lots of fancy features, like networking and, uh, lots of upper-case letters.

VMS and Unix sort of battled on. Or so some people would have you think. Really, Unix won early on and VMS stumbled along with corporate financing and an obnoxiously difficult-to-use interface. It passed from DEC to Compaq to HP, from the PDP-11 to the Alpha to the Itanium. And it still lives on, churning away in scary back-rooms here and there.

Current Events

So, why do I bring this up? Well, as some of you may know, Harvey Mudd College has a few VMS machines around. The most well-known of these (to students) is thuban, which is a 667MHz DEC Alpha running OpenVMS 7.3-2. Today, I had the, uh, interesting experience of using it, and thought I'd share my impressions with my readers. You can see the proof of my VMS skills at my VMS homepage. That's right, I'm on the Internet. And on DECnet.

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