Notes: Review of Operating Systems and Powershell Basics
Operating systems are necessary to allow humans to communicate with computers easier
- Generic term that refers to different open-source operating systems that are based on the Linux kernel
- Kernel was originally created by Linus Torvalds in 1991, and open sources in 1996
- A kernel is a piece of software that is designed to act as an intermediate layer between low-level hardware and high-level software, such as an operating system
- Most often used for servers because it's lightweight
One of the most well know Linux distributions
- Ubuntu is based on the Debian distribution family
- Kali is also based on the Debian distribution family
Another prominent Linux distribution
- Fedora - Based on the Red Hat family
Other notable families
- SUSE, Gentoo, Arch
The most commonly used shell in Linux systems is the Bourne-again shell, or Bash. The Bash shell is based on the Bourne shell, known as sh
A shell is, in essence, a user interface. Most often it is used to refer to a text-based interface, also called a command-line interface (CLI)
Nothing more than multiple Bash commands in sequence
Often used to automate repetitive tasks. They can be run interactively or non-interactively (meaning with or without user input) and can be shared with others
Windows is a group of user-friendly most graphical operating system families developed by Microsoft
Microsoft developed the NT kernel and based its OS on DOS. That is why writing commands for Windows differs from Unix-based systems
Powershell is a cross-platform task automation and configuration solution that is made up of a command-line shell, a scripting language, and a configuration management framework
- Windows Powershell is the new Microsoft shell that combined the old CMD functionality with a new scripting/cmdlet instruction set
Integrated Scripting Environment (ISE)
$ is used for defining and accessing variables in Powershell
Old style CMD commands and new style Powershell commands both work in Powershell
Get-Alias gives the new style powershell command name of old style CMD command names
Powershell's execution policy is a safety feature that controls the conditions under which PowerShell loads configuration files and runs scripts. It helps prevent the execution of malicious scripts.
AllSigned
- Requires that all scripts and configuration files be signed by a trusted publisher
- Prompts you before running scripts from publishers that you haven't yet classified as trusted or untrusted
- Risks running signed but malicious scripts
Bypass
- Nothing is blocked and there are no warnings or prompts
RemoteSigned
- Requires a digital signature from a trusted publisher on scripts and configuration
- Doesn't require digital signatures on scripts that are written on the local computer
Doesn't require digital signatures on scripts that are written on the local computer
Both / or \ as a path separator works. However, one way to be cross-platform is to always use /