Remove a Service:
# update-rc.d -f apache2 remove
cd /etc/init.d
# update-rc.d -f apache2 remove
Removing any system startup links for /etc/init.d/apache2 ...
/etc/rc0.d/K09apache2
/etc/rc1.d/K09apache2
/etc/rc2.d/S91apache2
/etc/rc3.d/S91apache2
/etc/rc4.d/S91apache2
/etc/rc5.d/S91apache2
/etc/rc6.d/K09apache2

Add a Service:
# update-rc.d apache2 start 91 2 3 4 5 . stop 09 0 1 6 .
Adding system startup for /etc/init.d/apache2 ...
/etc/rc0.d/K09apache2 -> ../init.d/apache2
/etc/rc1.d/K09apache2 -> ../init.d/apache2
/etc/rc6.d/K09apache2 -> ../init.d/apache2
/etc/rc2.d/S91apache2 -> ../init.d/apache2
/etc/rc3.d/S91apache2 -> ../init.d/apache2
/etc/rc4.d/S91apache2 -> ../init.d/apache2
/etc/rc5.d/S91apache2 -> ../init.d/apache2

1. Change IP Address:

Usually, you need to change from DHCP client to a Static IP address.

Recently, I killed my Linksys WRT54GL Router accidentally by upgrading it from HyperWRT to DD-WRT firmware.

Make sure the gs (Ghostscript) is installed, and type following command:

gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=finished a.pdf b.pdf

1. How To Create an ISO Image from a CD or DVD

1) Insert the CD or DVD that you want to make an ISO image of.

2) Open a terminal window.

3) Execute the following command:

cat /dev/scd0 > /home/your_username/image_file.iso

where /dev/scd0 is the device name for your drive (to find this, go to the Main Menu, click on System, mouseover Administration and select System Monitor. Click the File Systems tab. The device name will be listed in the Device column). Also make sure to change the path and iso filename to the desired path and filename.

The disc will begin to spin and the ISO image will start being constructed. Once it has completed, you have an ISO image of your CD. To verify that the image was properly created, mount the ISO file and check the contents.

2. How to burn ISO file to CD or DVD:

1) GUI: https://help.ubuntu.com/community/BurningIsoHowto

2) Command Line: https://help.ubuntu.com/community/CdDvd/Burning