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As you may already have heared, I am a big fan of Scala. I was asked to provide a few examples. I would not say that I am an expert, so I start with a really simple example.

Let's write a really simple RPN calculator which reads a term from STDIN and prints out the result. The simple thing about RPN is that we only need a stack to calculate the result. So we start with this a class that includes the stack.

There are many backup solutions out there. Many of them are free and each one is great in its own way. One very pouplar solution is BackupPC. But sometimes these solutions are to complex. Imagine the following scenario: you have exactly one tiny server and an FTP storage, and you want to do incremental backups every night via cron. It sounds like a problem for rsync. But since FTP and rsync don't work together that well, here is another solution: duply.

Hudson is a really great tool if you work with source code in a team with more than two persons. One thing in hudson always fascinated me: the fact, that Hudson is runnable just by typing

java -jar hudson.war

I do not know if it really has practical relevance, but I searched a way to create such a jar only with Maven and Jetty.

I already wrote about tiny tiny RSS (tt-rss) in this article.

So far, the login-mechanism of tt-rss was used. However, tt-rss also allows to use authentication mechanisms of an webserver, which allowes the usage of htAccess and htUser-Files.

The Horde framework is a great tool if you need a collaboration suite which is accessible from all over the world. In newer versions, Horde provides an rpc service which can be used to sync calendar-entries, contacts and notes.

I use a Nokia 5230 with an Symbian S60 5. Edition. It gives me the opportunity to sync my contacts, calendar and notes via SyncML. Wouldn't it be great to sync these with horde, so you have always the same calendar, even if you're offline?

Basically, all you have to setup is this:

• open Menu > Settings > Connectivity > Data transfer > Sync (Menü > Einstellungen > Verbindungen > Datentransfer > Sync in German)
• add a new sync profile with
• name: Horde
• version: 1.1
• channel: Internet
• connection: default
• server address: https://path/to/horde/rpc.php
• port: 443
• username: your horde login name
• password: your horde login password
• contact database: contacts
• calendar database: calendar
• notes database: notes
• (keep the default values for the rest)

Well, I would not blog about it, if it worked in the first try. My Phone said "connection error" ("Verbindungsfehler" in German). I google'd a few hours and found out only one important note: If you create a directory /tmp/sync, then horde will log some debug-output there. Horde did, and as far as I understood the files, they looked okay.

It was rather an accident that I found out what the problem was. It seems, by cellphone can't decompress HTML-Streams. In the horde administration, select "configuration" and open the "Horde (horde)" settings. Make sure that in the "general"-Tab in the "PHP Settings" section there is no tick at $conf[compress_page]. After I removed the settings, my cellphone was happy. And me too

Tiny Tiny RSS (aka "tt-rss") is a very nice tool if you read many rss feads from various devices. It's an alternative to Google Reader and runs on your own server. You only need a database (MySQL or Postgres) and PHP.

One of its features is a mobile view. This allows you to read news from you mobile phone. You just have to append /mobile to your url on your iWhatever (iPhone, iPad, iPod), or /mobile/classic on other mobile browsers.

A few hacks help to make the easier-to-read™ iPhone view available to other browsers. I tested it with Opera Mobile.

Have I already noted that I love Jabber? Jabber is relly great, and sometime I will write my own bot framework for it. In my oppinion jabber has great opportunities beyond pure chatting. I use Jabber as a kind of notification system for several things. E.g. for nagios (german). And since thunderbird consumes lots of ram only to show a notification about incoming mails, I decided to search a solution to provide Jabber notifications.

DokuWiki is a very simple, PHP based wiki. It's strengh is simplicity. It uses txt files for storage and runs on nearly every Webserver which supports PHP, no database needed.

DokuWiki supports Users and ACLs, so it's possible to allow editing only to a special group of people. DokuWiki supports many authentication backends, but the default plugins all assume that the wiki has a "login" button. In my case, the users are already authenticated via htAccess. So I started to search a solution which integrates these users.

I guess nearly every admin of a webserver knows the article ISP-style Email Server with Debian-Etch and Postfix 2.3 from workaround.org. I use a similar setup (with different pathes) for my private mailserver. I have a number of users and accounts and on some days I get a pretty high number of spam.

Step 11 of the tutorial shows an example how to automatically learn spams and ham. But I think, one can do this better.

I love aliases. There are many useful shortcuts, e.g. ".." as an alias for "cd ..". If I got shell access to a system, I first install my version of vimrc, bashrc, bash_alias, and so on. I keep those files in a subversion repository, so I can synchronize them.

But what to do, when aliases are "system-sensitive"?