PowerShell: Writing a Script - Paiet/Tech-Journal-for-Everything GitHub Wiki

Writing a Script

• Scripts are PowerShell commands stored in a file
  • .ps1 file extension
• Start with Get-Process script

Create new script
Get-Process
Save script
Check execution policy

• You can run PowerShell scripts by
  • Entering the entire path
  • Change to directory and use .\
    • Tab autofill will put .\
  • Right-click on script in file explorer -> Run with PowerShell

Double-click on script in explorer [fail]
test.ps1 from console [fail]
.\test.ps1 [success]

• Sort results descending by CPU

Get-Process | Sort-Object -Descending -Property CPU

• Filter results to top 10 and limit fields

Get-Process |
Sort-Object -Descending -Property cpu |
select -first 10 processname, id, cpu

• Add ability to choose how many

param(
    $top
)

Get-Process |
Sort-Object -Descending -Property cpu |
select -first $top processname, id, cpu

• Show properties available for Get-Process

Get-Process | Get-Member

• Add ability to choose property

param(
    $category,
    $top
)

Get-Process |
Sort-Object -Descending -Property $category |
select -first $top processname, id, $category

• Modify parameter properties

param(
    [parameter(mandatory=$true)][string]$category,
    [int]$top = 10
)

• Format output

$format = @{label="Memory(Mb)";expression={[int]($_.ws/1mb)}}

• Use IF statement to fix formatting

if ($category -eq "ws"){
    $format = @{label="Memory(Mb)";expression={[int]($_.ws/1mb)}}
} else {
    $format = $category
}

• Probably should use SWITCH but for now fix IF

if ($category -eq "ws") {
    $format = @{label="Memory(Mb)";expression={[int]($_.ws/1mb)}}
} elseif ($category -eq "pm") {
    $format = @{label="Memory(Mb)";expression={[int]($_.pm/1mb)}}
} else {
    $format = @{label=$category;expression={[int]($_.$category)}}
}