File I/O

Get the contents of a file with Get-Content:

Get-Content "README.txt"

The contents of the file are stored line-by-line in an array:

$a = Get-Content "README.txt"
$a[0]    # First line of the file
$a[3]    # Fourth line of the file

To combine the contents of a file into a single string, use [string]::Join():

$a = Get-Content "README.txt"
$separator = [System.Environment]::NewLine    # could have done `r`n
$all = [string]::Join($separator, $a)

To write to disk, use Set-Content:

Set-Content -Value $all -Path "New-file.txt"

Import Powershell from another file using Import-Module:

Import-Module "C:\Temp\Utility.ps1"