NewInstance

Forcing fsck on next reboot

$ sudo touch /forcefsck
$ sudo reboot

Merging PDFs

$ sudo apt-get install pdftk
$ pdftk file1.pdf file2.pdf file3.pdf file4.pdf cat output merge.pdf

Formatting USB disks/memories

mkfs -t vfat -V -I -c /dev/sdb -n LABEL
eject /dev/sdb

Fixing Oracle Repository GPG/PGP Key Error

The error (in Synaptic or during “apt-get update”):

W: GPG error: http://oss.oracle.com unstable Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 2E2BCDBCB38A8516
W: You may want to run apt-get update to correct these problems

The solution:

$ sudo wget http://oss.oracle.com/el4/RPM-GPG-KEY-oracle -O- | sudo apt-key add -

Editing Gnome Menus

$ cd ~/.local/share/applications

then check the contents and add/edit/remove *.desktop

VirtualBox Tips

1. Install it: it’s fantastic!
2. Install from Download Sun xVM VirtualBox 1.6, not from Synaptic. If you want all the feature don’t go for the Open Source Edition (OSE).
3. In ubuntu I use OSS Audio Driver with Controller ICH AC97. With others I got audio problems.
4. Install the guest additions (Devices Menu=>Install Guest Additions), you’ll have very cool features like the seamless integration, mouse integration, and the screen resizing to fit the window size, and more.
5. If you want the USB support (not available in the OSE), you will face two errors:
The first: “Could not load the Host USB Proxy Service (VERR_FILE_NOT_FOUND). The service might be not installed on the host computer. “
Solution: edit the file /etc/init.d/mountdevsubfs.sh and uncomment the following lines

	#
	# Magic to make /proc/bus/usb work
	#
	mkdir -p /dev/bus/usb/.usbfs
	domount usbfs "" /dev/bus/usb/.usbfs -obusmode=0700,devmode=0600,listmode=0644
	ln -s .usbfs/devices /dev/bus/usb/devices
	mount --rbind /dev/bus/usb /proc/bus/usb

Then if you try to use USB devices you’ll probably get another error: “Not permitted to open the USB device, check usbfs options.”
Solution: add to /etc/fstab

none /proc/bus/usb usbfs devgid=85,devmode=666 0 0

Adding more executable binary format support to Linux.

The command to do this magic is update-binfmts, not very difficult to use, but to learn try:

$ update-binfmts --display  // to see the list of associations
$ man update-binfmts        // to learn how to use it