Very simply, the reason why you want to learn how to create Powershell scripts is because a script can be automated. Even if you only save 5 minutes by automating a task, if you have to perform that task 5 times a day - you still save 25 minutes.
PowerShell scripts have the .ps1 extension. If you have already selected an IDE for your scripting, you can go ahead and open it. Create a .ps1 script and name it "Hello.ps1".
in the script add - write-output "Hello".
To run the script go down to the powershell command line and type in .\Hello.ps1.
Achtung: if you get an "unauthorized access warning" in red text and your script doesn't run. It means that you need to change your execution policy so you can execute PS scripts on your system. You do this with the Set-ExecutionPolicy command. To get the information you need to do this, please visit this Microsoft technet page. You must have an overview of the different Execution-Policies before you set a policy and talk to ICT first. Setting the policy to "unrestricted" might not be the best choice...
Just like a shell script in Linux, you must type in a "." to run the script. In this script, we just added a command, unlike the typing in write-output at the command line, you can schedule this script to run whenever and as often as you like. Here are some of the basics you need to know about scripting -
| PowerShell Script Basic Property | Value | Description |
|---|---|---|
| PS Script file extension | .ps1 | Use this extension to enable Windows to recognize that this is powershell. |
| Run a PS script | .<ScriptName>.ps1 | From the PS-prompt use this sytax to tell PowerShell to run a script |
| PS Script variable character | $ | To declare a variable prefix the variable name with a "$" |
| PS Script escape character | ` | for special characters in a string use the "`" to escape them. Example: "three `$Horses" escapes the "$" to text. Normally this would be the value of the variable $Horses. |
| PS Script pipeline character | | | to pipe output to the next cmdlet just like in the console |
| PS Script member enumeration | (command -parameters).property | This technique is used to retrieve single properties of an object. |
| PS Script optional arguments | [ ] | Access members of an array. Set DataType.. |
| PS Block Statement | { } | Used in cmdlets and in scripts. Block statements can be seen as query filters. Like in the where-object statements in earlier chapters. |
| PS Grouping | () | Groups statements together that need to execute first. see member enumeration. Also, for loops and conditional statements () is used just like in most code. |
| PS Script comment | # | document your scripts... |
The "$" symbol represents a variable in PowerShell both at command line and in scripts.
Example:
$secondsPerDay = 24 * 60 * 60
$weeksPerYear = 365 / 7
Parameters are useful for taking input and reading them into your script. They are like arguments for methods. In Powershell, you add parameters to your script with the param keyword. You can also set all kinds of attributes for instance if a parameter is required or optional. These attributes are described here.
Example:
Param(
[string]$computerName,
[string]$filePath
)
- Learn how to enable running scripts.
- Learn the usage for PS operators and operands.
- Write and run the "Hello World" ps script.
- Get a reference for the functions of syntax in scripts