Unit 5 Research Assignment 1
PT1420

* A shell script is a computer program designed to be run by the Unix shell, a command line interpreter. The various dialects of shell scripts are considered to be scripting languages. * Advantages of using shell script is that the commands and syntax are exactly the same as those directly entered at the command line. The programmer does not have to switch to a totally different syntax, as they would if the script were written in a different language, or if a compiled language was used. Often, writing a shell script is much quicker than writing the equivalent code in other programming languages. The many advantages include easy program or file selection, quick start, and interactive debugging. A shell script can be used to provide a sequencing and decision-making linkage around existing programs, and for moderately sized scripts the absence of a compilation step is an advantage. Interpretive running makes it easy to write debugging code into a script and re-run it to detect and fix bugs. Non-expert users can use scripting to tailor the behavior of programs, and shell scripting provides some limited scope for multiprocessing. * Most common usage methods of PowerShell is interactive console (powershell.exe) and script files (with extension of .ps1, that is also usually executed by powershell.exe). Main features of PowerShell are: .Net integration, object pipeline, easy access to many management domains (WMI, ADSI, COM, .NET etc.) and standartization that brings easy discovery and quick learning of new features after you know base functionality. PowerShell uses special commands called cmdlets (pronounced 'command-lets') that can use .Net objects in input and output. PowerShell can also use legacy command line utilities.
To provide access to hierarchical structures like file system, registry, certificate storage and so on, PowerShell uses "providers" that expose this structures in a file-system like way. For example you can use same commands and approach to change directory into file folder or registry key, etc.
External applications can host PowerShell as to use it as automation engine, and even build a graphical user interface above it (for example Exchange, VMM). This allows new approach to automating applications: you can use graphical interface and wizards in applications to perform actions, then get script for that actions, modify it and use for automation.