Check Disk Space Usage from Terminal in Ubuntu/Linux

To view disk space usage of your partitions/hard drive in your terminal, use the following command:

 df -h  

You should get result as shown in the image below:

Click on image to enlarge

How To Clear MySQL Screen In Ubuntu/Linux Terminal

While at your MySQL terminal enter the command below:

 mysql> \! clear  

Correctly Installing Kali Linux Headers

You might have wanted to install Guest Addition modules in Kali Linux under VirtualBox but failed due to failure of Kali Linux Headers. To solve execture the commands below in your terminal:

1. Find your header type by executing the following command:

 uname -r  

You should get output, depending on your version as:
3.18.0-kali3-amd64

2. Next execute the command below:

 apt-cache search amd64 headers  

3. Once you got the header information use it as below to download the latest header for your Kali Linux:

 apt-get install linux-headers-3.18.0-kali3-amd64 -y  

Your header should now be updated

Alternative to Adobe Reader in Ubuntu 14.04 for Anottation, Text Hightlighting etc...

I found this wonderful alternative to Adobe Reader for Ubuntu/Linux and it's called Okular which is a free software PDF reader.

What is it?

Here what there website says:

Okular is a universal document viewer based on KPDF for KDE 4. This means Okular works on multiple platforms, including but not limited to Linux, Windows, Mac OS X, *BSD, etc.

Okular combines the excellent functionalities of KPDF with the versatility of supporting different kind of documents, like PDF, Postscript, DjVu, CHM, XPS, ePub and others.

The document format handlers page has a chart describing in more detail the supported formats and the features supported in each of them.

 Okular gives you various options such as annotation, text highlighting, text extraction etc.

To install Okular in your Ubuntu:

 sudo apt-get update  
 sudo apt-get install okular  

Enabling USB WiFi Network Adapter in VirtualBox with Kali Linux as Guest OS

I found enabling USB WiFi Adapter in Window 7 much simpler than Linux, precisely Kali Linux. Not that I couldn't do it in Kali but after sometime the connection would drop. But with Windows 7 it didn't take me a fraction of time compared to Kali and with the method I discovered the connection is also not dropping in Kali now.

So here's how to do it with Kali Linux as Guest OS. You can also use the same technique while using other OS such as Windows as Guest OS:

1. First make sure you have  added yourself to the user group 'vboxusers'; else you will be unable to view your Wireless USB Network Adapter under the  USB Devices list.

2. Now you can select your Network Adapter by going to --> Devices -->  USB Devices --> Select your Network Adapter here

Now to save yourself from your 'connection getting dropped' every now and then, make sure you have disabled your Internet connection from your Host OS. See the image below.

 

To confirm your WLAN setup Open your terminal and type:

 ifconfig  

You should be seeing something like wlan0 along with the details as in the image above.

Sharing Drive/File/Folder in VirtualBox with Ubuntu as Host and Kali Linux or Windows as Guest OS

1. To Share Drive/Folder in Kali Linux as Guest OS:

First make sure your Guest OS is turned off else you won't be able to make the changes.

 Then on your VirtulaBox Management Page make the following changes as shown in the above image or continue to read below:

1. Click on Settings
2. Click on Shared Folders
3. In 'Folder Path' select the desired Drive/Folder/File
4. If you just want to read the files from your Guest OS the select Read-only else if you want to read/write leave it as it is.
5. Give a name to your folder in 'Folder Name'.
6. Select Auto-mount if you would like to mount your drive/folder/file on startup.
7. Finally Click OK and that's all there is to 'Sharing Folders' in Virtual Box.

If you are using Kali Linux you can locate your drive/folder/file under '/media/your_shared_drive_folder_file'