Linux : How to copy/remove all files from a tree of directories.

Sometimes we face a situation when there are a huge or rather say a deep tree of directories. All these directories in turn contains directories and files and at the leaf node i.e. in the innermost directory there are some files.
Now you want to copy all files at one place or say you want to perform some action on all these or some selected files.

How to remove Ubutnu if installed on seperate partition (Dual Boot system)

If you have installed Linux on its own partition in a dual-boot configuration, there’s no easy uninstaller that will remove it for you. You will need to delete its partitions and repair the Windows boot loader on your own.
To remove the Ubuntu from your system, follow these steps.

Deleting Linux Partition.

Checking RAM size , Usage in Ubuntu

To check the RAM usage in Ubuntu , there are these two(out of many others) methods -

1. use command

$ cat /proc/meminfo

VI editor : Arrow keys and Backspace keys are not working properly.

It has been found that on a new installation of Ubuntu [lets say 13.04] , when you try to write some code in VI editor, the arrow keys are not working as expected.
It becomes very frustrating when you wants to navigate in the code using arrow key and instead of cursor moving up and down you see characters like A , B , C or D in middle of text.

Few very dangerous commands in Linux

NOTE : DO NOT RUN these commands on your machine. Use friend's system. :)

So in Linux there are many simple, short and efficient commands which can be very harmful if are not used with precaution. 

1. sudo rm -rf /

 This command remove all the content from root(/) directory when hit enter after providing password. This is one reason our default working user is not root.

2. :(){ :|: & };:

Windows-8 : NTFS drives are not accessable in Ubuntu/Linux.

In windows 8, there is a feature of "fast start-up" which is somehow equivalent to hibernate. It saves your system state in hibernate.sys file so that when next time you boot up the system it takes just few seconds to start.
This feature is enables by default and most of the users are unaware of it.

But this feature cause a problem to Linux users. When you boot the Linux OS and try to mount the drives it throws the error and doesn't allow you to access it.

Disabling Guest login in Ubuntu 13.04

1. Open the terminal (cntrl + Alt + t).

2. Run the command
    
   sudo gedit /etc/lightdm/lightdm.conf