It’s in beta right now, and you’ll need to apply with your gmail account before you can use it, but it looks like a great learning tool that may lure many young minds into the world of software development. As the tools get more powerful in the future, the quality of apps created using Google App Inventor should grow.

Ever want to see the structure of some directories from the command line just like you can in a nautilus or windows explorer interface? Try the UNIX port of the DOS tree utility. Chances are you probably already have it installed on your desktop system.

This one should be pretty bulletproof. Use a single sed command to dump the list of all ip addresses from interfaces showing in ifconfig.

Instead of killing the process in order to run dhclient to get a new lease, just release it. See? No need to kill it. Now you can ask for another lease.

With rpmbuild, you can make custom packages for any architecture, but what if there’s no difference between the architectures in what you’re building. If you’re copying around something like scripts, docs or other text files that have nothing to do with 32 vs 64 bit or endianness, it’s easier and more efficient to create a single noarch package and just keep one copy of it in a repository.

Do letters show up when you hit the arrow keys in edit mode? If you like to use the arrow keys in vim/vi, you will quickly notice that Ubuntu appears broken. Welcome to vim compatibility mode. It’s just a setting that Ubuntu defaults to…

These packages are not available in the out-of-the-box configuration when you install Ubuntu 10.04. To get sun java packages such as sun-java6-jre or sun-java6-doc, you need to give yourself access to additional repositories… Now try searching for or installing one of those packages you were missing.

VirtualBox can’t operate in VMX root mode. Please disable the KVM kernel extension, recompile your kernel and reboot. You might see this VirtualBox error when trying to start a virtual machine or create a new one.

If you need to forward X the old school unencrypted way, you need to add one line to gdm’s custom.conf file and restart the desktop. Without this, the old “xhost +” won’t do a thing because the out of the box Xorg configuration includes the nolisten tcp flag.

So easy, and it works with lists too. Won’t work with dictionaries but it should work with any hash-able type.