Kali Linux consists of hundreds of pieces of application software and an operating system kernel. You may need to update the software if you want to get the latest features.
We suggest that you only update the software and kernel from the Kali Linux software package repository.
The first thing to do after you have successfully installed and configured Kali Linux is to update it. As Kali is based on Debian, you can use the Debian command (apt-get) for the updating process.
The apt-get command will consult the /etc/apt/sources.list file to get the update servers. You need to make sure that you have put the correct servers in that file.
The default sources.list file included in Kali Linux contains the following entries:
# deb cdrom:[Debian GNU/Linux 2.0 _Sana_ - Official Snapshot i386 LIVE/INSTALL Binary 20150811-09:06]/ sana contrib main non-free #deb cdrom:[Debian GNU/Linux 2.0 _Sana_ - Official Snapshot i386 LIVE/INSTALL Binary 20150811-09:06]/ sana contrib main non-free deb http://security.kali.org/kali-security/ sana/updates main contrib non-free deb-src http://security.kali.org/kali-security/ sana/updates main contrib non-free
You need to synchronize the package's index files from the repository specified in the /etc/apt/sources.list file before you can perform the update process. The following is the command for this synchronization:
apt-get update
Make sure that you always run an apt-get update before performing a software update or installation in Kali. After the package index has been synchronized, you can perform software updates.
Two command options are available to perform an upgrade:
apt-get upgrade: This command will upgrade all of the packages that are currently installed on the machine to the latest version. If there is a problem in upgrading a package, that package will be left intact in the current version.apt-get dist-upgrade: This command will upgrade the entire Kali Linux distribution; for example, if you want to upgrade from Kali Linux 1.0.2 to Kali Linux 2.0, you can use this command. This command will upgrade all of the packages that are currently installed and will also handle any conflicts during the upgrade process; however, some specific action may be required to perform the upgrade.
After you choose the appropriate command option to update Kali Linux, the apt-get program will list all of the packages that will be installed, upgraded, or removed. The apt-get command will then wait for your confirmation.
If you have given the confirmation, the upgrade process will start. Beware, the upgrade process might take a long time to finish depending on your Internet connection speed.