Sunday, April 17, 2016


Wednesday, March 16, 2016

How to Concatenate Images with ImageMagick (convert)

convert image1 image2 -append result


convert image1 image2 +append result

Monday, March 14, 2016

How to Lock the Screen After Coming Back from Suspend (Sleep)

Locking the screen saver on hibernate or suspend

You may wish to run a screen locking utility when the system suspends (so that a password is required after waking up). This can be done by adding a script to the /etc/pm/sleep.d folder. Make sure the script is executable (chmod 755) and owned by root:root.

A simple example script is:

 #!/bin/sh   #   # 00screensaver-lock: lock workstation on hibernate or suspend     username= # add username here; i.e.: username=foobar   userhome=/home/$username   export XAUTHORITY="$userhome/.Xauthority"   export DISPLAY=":0"      case "$1" in      hibernate|suspend)         su $username -c "/usr/bin/slimlock" & # or any other such as /usr/bin/xscreensaver-command -lock      ;;      thaw|resume)      ;;      *) exit $NA      ;;   esac

Saturday, October 17, 2015

How to Auto Mount NFS in Mac OS X Yosemite! Permanently


/myserver auto_myserver


Add the following lines to this file:

MyShare1 myserver.local:/exported/path/MyShare1
MyShare2 myserver.local:/exported/path/MyShare2

To check if mounting works, run:

sudo automount -vc

The shares should have been moun

Sunday, September 13, 2015

x2go viewport issue when remote resolution is higher than client resolution

In that case, moving viewport doesn't work (could be a bug).  But we can use "ctrl+atl+MOVING_MOUSE" to move the viewport!

Thursday, September 10, 2015

How to turn your Ubuntu Unity Window Manager into Grayscale

First, install the packages "compizconfig-settings-manager" and "compiz-plugins-extra". Use this command:
sudo apt-get install  compiz-plugins-extra compizconfig-settings-manager
Then open the program ccsm (CompizConfig Settings Manager). It contains a plugin called "Opacity, Brightness and Saturation" which controls the opacity, brightness and saturation of windows.

However, after experimenting for a while, it appears that this plugin cannot be applied to the Unity launcher and panel, since probably it's composited differently than the rest of the desktop (this problem also affects the zoom plugin). It means that this plugin can make any part of your screen (desktop background, windows, etc. etc.) black and white BUT the launcher and panel. So, unless someone knows something that I don't, what you're asking for is impossible.

If you are still curious as to how to make a window black and white, then: In ccsm, enable the plugin "Opacity, Brightness and Saturation". Wait a while for Compiz to sort itself out, then open it, go to the "Saturation" tab. On the second "Increase Saturation" entry, click it, choose "Ctrl", "Alt", and "Button4". Same for the second "Decrease Saturation" entry, but "Button5" instead of "Button4".

Now, hover your mouse on any windows, hold Ctrl + Alt and scroll down with the middle mouse button to make your window go black and white! To make it colorful again, Ctrl + Alt + Scroll up. This might be enough to amaze your friend.

Wednesday, June 17, 2015

no common cd rom drive was detected

When installing Debian from external USB harddisk, you might encounter
this error message:

"no common cd rom drive was detected"

Just enter "No" and enter "/dev/sdb"



Monday, June 15, 2015

how to restore grub with encrypted partition (dm-crypt)

If you have an encrypted parition with dm-crypt for "/" and your GRUB
is corrupted (or wiped after installing other operating system onto the
same computer), please follow these tips.

- grub-install and update-grub need to be executed under chroot'ed.

This is the most important tip. You must chroot into the encrypted
partition first.

- cryptsetup luksOpen /dev/sda3 csda3
- mount /dev/mapper/csda3 /mnt/system
- (assuming csda3 is /)
- (assuming sda2 contains an unencrypted /boot for this operating
- mount /dev/sda2 /mnt/system/boot
- mount -o bind /dev/ /mnt/system/dev/
- mount -o bind /proc/ /mnt/system/proc/
- chroot /mnt/system
- grub-install /dev/sda
- update-grub

Friday, June 12, 2015