Ubuntu is an example of Linux.
Linux is a Unix-like and mostly POSIX-compliant computer operating system assembled under the model of free and open source software development and distribution. The defining component of Linux is the Linux kernel, an operating system kernel first released on 5 October 1991 by Linus Torvalds. The Free Software Foundation uses the name GNU/Linux, which has led to some controversy.
Linux was originally developed as a free operating system for Intel x86-based personal computers. It has since been ported to more computer hardware platforms than any other operating system. It is a leading operating system on servers and other big iron systems such as mainframe computers and supercomputers. More than 95% of the world's 500 fastest supercomputers run some variant of Linux, including all the 44 fastest. Linux also runs on embedded systems, which are devices whose operating system is typically built into the firmware and is highly tailored to the system; this includes mobile phones, tablet computers, network routers, facility automation controls, televisions and video game consoles. Android, which is a widely used operating system for mobile devices, is built on top of the Linux kernel.
The development of Linux is one of the most prominent examples of free and open source software collaboration. The underlying source code may be used, modified, and distributed—commercially or non-commercially—by anyone under licenses such as the GNU General Public License. Typically, Linux is packaged in a format known as a Linux distribution for desktop and server use. Some popular mainstream Linux distributions include Debian, Ubuntu, Linux Mint, Fedora, Arch Linux, and the commercial Red Hat Enterprise Linux and SUSE Linux Enterprise Server. Linux distributions include the Linux kernel, supporting utilities and libraries and usually a large amount of application software to fulfill the distribution's intended use.
A distribution oriented toward desktop use will typically include X11, Wayland or Mir as the windowing system, and an accompanying desktop environment such as GNOME or the KDE Software Compilation. Some such distributions may include a less resource intensive desktop such as LXDE or Xfce, for use on older or less powerful computers. A distribution intended to run as a server may omit all graphical environments from the standard install, and instead include other software to set up and operate a solution stack such as LAMP. Because Linux is freely redistributable, anyone may create a distribution for any intended use.
List of Linux distributions
- Tails: Tails serves as a pre-configured out-of-box secure OS which can be easily loaded onto removable media. Its ease of use while still forcing a secure protocol makes this OS a great contender. It's based on Debian. All its outgoing connections are forced to go through Tor, and non-anonymous connections are blocked. https://tails.boum.org/
- Whonix: As with Tails, Whonix forces all communication through the Tor network. However, Whonix uses VirtualBox to usd a VM to ensure isolation of the user from the network. As such, it is a little more complex to setup and maintain. Nonetheless, Whonix serves as a viable alternative to the Tails OS for any user who wishes to keep a persistent OS on disk. It's based on Debian. https://www.whonix.org/
- Kali Linux: While not geared towards being out of the box secure, Kali is a powerful tool to exploit network vulnerabilities. This OS comes prepackaged with tools to collect and analyze data in your network as well as having software for anti-forensics. If you have ever wanted to know how secure your system/network is - bombard it with Kali. Kali Linux is the new generation of the industry-leading BackTrack Linux penetration testing and security auditing Linux distribution. Kali Linux is a complete re-build of BackTrack from the ground up, adhering completely to Debian development standards. https://www.kali.org/
Linus Torvalds, the founder of Linux kernel joked during a LinuxCon keynote 18 September 2013, that the NSA, who is the founder of SELinux, wanted a backdoor in the original kernel. However later, Linus' father, Member of the European Parliament (MEP), revealed that the NSA actually did this.
When my oldest son [Linus Torvalds] was asked the same question: “Has he been approached by the NSA about backdoors?” he said “No”, but at the same time he nodded. Then he was sort of in the legal free. He had given the right answer, [but] everybody understood that the NSA had approached him. -- Nils Torvalds, LIBE Committee Inquiry on Electronic Mass Surveillance of EU Citizens - 11th Hearing, 11 November 2013
Frequently used commands
cd and ./
"cd" command changes a directory.
For example, in your home directory, if you type "cd tor-browser_en-US/", then the directory changes to "tor-browser_en-US/". It is same to "cd ./tor-browser_en-US/".
"." means your current directory.
".." stands for your upper directory.
If you input "cd ..", then your directory changes into the upper directory.
If you are in "tor-browser_en-US/" directory, you can excute Tor Browser. Just type "./s" and press "Tab" key, then "./start-tor-browser.desktop". will be automatically completed.
Not confuse "cd ./example" with "./example". "cd ./example" is changing a directory and "./example" is excuting a file.
Hot to mount an external H.D.D.
Change a passphrase of LUKS
For more detail, see Ubuntu.