Too Far Afield

I’ll be in Braunschweig on Sunday, Monday and Tuesday. I won’t have an internet connection at my disposal so don’t expect any email communication till later this week. Call me on my mobile phone to get in touch.

This clearly is a post for novice Linux users, but never mind. This will be the first part of a series, where I cover some very basic Linux commands and techniques, that come in handy for system administrators.

One of these commands is tail. You might compare it to a wordprocessor. With tail you can print the last lines of a file on your screen.

Often you’d like to see the last lines of a log file to check what is going on. Instead of opening the file in your favourite editor and scrolling all the way down you could as well type

1. tail /var/log/syslog

to print the last 10 lines of the syslog file to standard output – that is your screen. You see why this command is a must have for every system administrator.

But wait. There’s more! You can easily tell tail to use something I will call monitoring mode (Alliteration, I hear you!). In that mode, tail will monitor the given file and print new lines to standard output as they appear. That’s good, if you want to test a new configuration and need to check log input in real-time. Use the f parameter:

1. tail -f /var/log/syslog

I hope this one was good for you. Stay tuned for more interesting commands and procedures to be published next week.

Heute spricht das Volk und die Politiker dürfen schweigen.

Joschka Fischer, The Greens.

Says the man behind the counter. Live from my postbox: Wir können Ihnen die erfreuliche Mitteilung machen, dass Sie zum Wintersemester 2005/2006 für den Studiengang Bachelor of Science (B.Sc.) Informatik zugelassen worden sind. That means I won’t move to another city anytime soon. Yay!

While filing a number of Tech Evang bugs in the Mozilla bug tracking system this morning, I had to do a lot of whois lookups. Since every developer should use his own code I used yourwhois.de. And – surprise, surprise – I found a few bugs. The copy paste feature did not work for secure domains (https://) and br and sg were not recognized as domains that use public second level domains. Those issues are now fixed. Also our copy-paste feature did not work at all with our searchplugin for Mozilla browsers, which is furtunately still in beta. That one is fixed, too.

We just upgraded our Xinetd service to a new version. That should not have been problematic. However, we have a special setup. On our servers pop3 service is managed via Xinetd, because it gives us better access control and more flexible logging. Due to our restrictive secure site policy, pop3s service is mandatory for all of our customers. Until now we were able to use Xinetd to run an old-style insecure pop3 service only on localhost. This pop3 service is needed by our webmail application, which is built on top of some PEAR libraries that do not support the secure pop3s service right now.

But what happened after the upgrade? Our webmail application no longer worked. That was, because the local pop3 instances no longer responded. The solution to the problem was to replace

1. only_from: localhost

with

1. only_from: 127.0.0.1

Simple, isn’t it? It took me just two hours of try and error routine to figure this out. Doh!

If you use a standard MySQL server and want to sort your German entries in alphabetical order, you might notice that the entries are actually sorted wrong. For example, entries starting with ös will appear after entries starting with us.

For our non-German readers I’d like to say that if you want to sort German umlauts you need to translate them as outlined below. This procedure also applies to crossword puzzles.

ä

ae

ö

oe

ß

ss

ü

ue

Back to the original problem: Why does MySQL sort the entries wrong? The simple answer is, that it tries to sort it using a Swedish character set, which is the default character set of the official MySQL distribution, because – and I quote MySQL documentation here – it works well for most of western Europe and America. You can “fix” this by using special command line options at server startup time. Possibly you also need to alter your existing mySQL databases and tables. But be warned: You have to throw away any indexs before you convert your tables and recreate them afterwards. Otherwise nothing will happen at all.

Consult the MySQL documentation for a detailed description of the above:
Using the German Character Set.

A few days ago a customer asked me what computer magazine I read. That was after I told him, that I didn’t like Computer Bild that much. Ah, c’t, he said knowingly. I once bought that unintentionally, but I did not understand that much. Good journalism without useless compact disk additions since 1982 1983.

In related news, my Schlafhaushalt is a total mess again these days. At least after the last infamous night shift.

Bei diesem Rezept handelt es sich um ein altes Familienrezept. Es wurde bisher immer nur mündlich überliefert. Das Rezept ist für ein Backblech.

Zutaten

• 1000g Zwiebeln
• 250ml frische Vollmilch
• 2 EL Sonnenblumenöl
• 500g Mehl Typ 405
• 250g Saure Sahne
• 1 Paket Trockenhefe
• 1/4 Paket Butter
• 4 Eier
• Schinkenwürfel
• Salz, Pfeffer, Muskatnuss
• Optional Kümmel

Zubereitung

Einen Hefeteig ansetzen. Für alle, die nicht wissen wie das geht, hier die Vorgehensweise mit Backautomat: Die Milch in der Mikrowelle für 30 Sekunden bis 1 Minute lauwarm erhitzen und in den Automaten einfüllen. Sonnenblumenöl und Mehl hinzugeben. In der Mitte eine Mulde machen und die Trockenhefe hineingeben. Am Rand 1/2 Teelöffel Salz streuen. Auf Programm “Teig kneten” stellen.

Für den Belag zunächst die Zwiebeln schälen und klein hacken, in Butter ca. 1 Stunde bei mittlerer Hitze hellgelb dünsten. Es ist wichtig, dass die Zwiebeln wirklich alle gut gedünstet sind, sonst schmeckt es nachher nicht! Nichts anbrennen lassen, also regelmäßig wenden. Zwiebeln in eine Schüssel geben und abkühlen lassen.

In einem Becher die Saure Sahne mit den Eiern verquirlen. Mit Salz, Pfeffer und ordentlich Muskatnuss würzen. Optional etwas Kümmel hinzugeben. 2 Teelöffel Mehl unterrühren und alles mit den Zwiebeln vermischen.

Den Teig auf ein Backblech auswellen und die Zwiebeln darauf gleichmäßig verteilen. Dann mit Schinkenwürfeln bestreuen (außer man ist oder kocht für Vegetarier). Auf mittlerer Schiene im Backofen bei Umluft oder Multiheißluft (150 °C) goldgelb backen. Vorsicht, nicht zu lange backen, sonst sitzt der Belag herunter und es schmeckt nicht ganz so gut. Wenn es langsam dunkler wird, sollte man sich Sorgen machen.

Guten Appetit!