VirtualBox is a free tool, which allows you to run virtual machines on a host computer. Using VirtualBox you can install Linux, Windows and other operating systems to play and experiment with.

Start the process by closing virtualbox (I usually also dettach the virtual harddisk due to be resized). Go on to a shell and find the directory where the virual machines are located.

If your initial harddisk was cloened from another virtualbox, you may get an error like this:

While it really isn’t secure at any measure, ftp is a very useful way of moving files around. Apple’s OSX have a build-in basic ftp server, but in Lion (version 10.7) the user interface seems to have disappeared from the User interface. The servers is still available under the hood if you need it.

To enable the ftp-server (the availability) enter this command in a terminal window:

sudo launchctl load -w /System/Library/LaunchDaemons/ftp.plist

I’m in the process of reinstalling my work desktop. One of the mandatory packages which I install once the core system is up and running is a SSH Daemon. Setting it up (on Linux Mint which I’m running) is pretty easy. To install the OpenSSH daemon go to the shell and write:

sudo apt-get install openssh-server

It’s a fairly small install, so in a few seconds it ought to be up and running. Next step is editing the default config file and change a few things. Editing the config file is done by entering:

PHP like many other programming languages has facilities to handle exceptions. Using them is pretty easy, but sometimes lazy programmers seems to misuse them to suppress error messages. A try/catch in PHP is usually constructed something like this:

try {
	// Something can go (horribly) wrong...
} catch {
}

The lazy programmer may leave the catch empty, but frankly you should never do it. When you’re doing something - try’ing - it’s for a reason, and if it fails, someone quite possible need to know - the end user, a log file for the sysadm or someone else. Never leave your catch empty, and if you really have a case, where it’s applicable, at least leave a comment in catch block explaining why it’s okay to do nothing.

In PHP when you have a string and want to find out if it contains another string, there are a few ways to do it. You can use regular expressions, use the strstr functions and a few other methods. The easiest way though is probably by using strpos, which returns the number of the character containing the first occurrence of the thing you’re looking for - and false if the string isn’t found.