Kali Linux is successor of BackTrack operating system that is developed by Offensive Security . Kali Linux comes as a full fledged o.s. for penetration testing. It has softwares preinstalled like Wireshark, Kismet, Metasploit framework, Aircrack ng, John the ripper and many many more tools for password cracking, data recovery, digital forensics and penetration testing by performing various attacks on websites and wired and wireless networks. But if you want to use Kali Linux as a your only o.s. for all your daily work then there are some softwares that you need to install. This softwares includes alternatives to Windows softwares in linux like Microsoft Office, Internet Explorer, Notepad, Outlook Express, uTorrent, Windows Media Player, Winzip etc.