VirtualBox 4 USB support in Linux

Download VirtualBox Oracle VM VirtualBox Extension Pack and install it by VirtualBox → File → Preferences... → Extensions → Add package.

Then grant vboxusers groups access to the USB device filesystem:
$ grep 108 /etc/group
$ vim /etc/fstab
usbfs  /proc/bus/usb  usbfs  auto,busgid=108,busmode=0775,devgid=108,devmode=0664  0  0

Password protected GRUB Legacy

Add password into the main GRUB section to password protect the interactive operations (i.e. editing menu entries and entering the command-line interface). Optionally add lock into a menu entry to prevent it from executing if no valid password is provided by the user.
$ grub-md5-crypt 
Retype password: 

$ chmod 600 /boot/grub/menu.lst
$ vim /boot/grub/menu.lst
default 0
password --md5sum $1$K0Kh10$OmQNQOthH8jppDFQ5TYx5/

title Linux
kernel ...

title OpenBSD
kernel ...

Create a svn tag from trunk

svn mkdir -m "release directory"
svn copy \ -m "release 1.0"

Nicer Oracle Date Output

Oracle date output including full year, month, day, hours, minutes and seconds:
SQL> alter session set nls_date_format = 'yyyy-mm-dd hh24:mi:ss';
SQL> alter session set nls_timestamp_format = 'yyyy-mm-dd hh24:mi:ss';
SQL> select foo_date from bar_table where rownum <= 1;

2012-01-01 01:02:03

Tunneling VNC connection

Connect to a VNC server listening on localhost on port 5901 (+1 than usual) using tunneling:
vncviewer -via yourusername@remotemachine localhost:1

How to build RPM packages as a regular user

Install the necessary packages as root:
sudo yum install rpmdevtools rpm-build redhat-rpm-config
Initialize the directory hierarchy for your custom build RPM packages as a regular user:
Optionally add additional attributes into ~/.rpmmacros, e.g.:
echo '%packager Your Name <>' >> ~/.rpmmacros
Use rpmbuild to build RPM from a source RPM or from a SPEC file:
rpmbuild --rebuild package.src.rpm
rpmbuild -bb package.spec