#Requires -Version 2.0

Function New-RandomString {
    Param([string]$source="123abcDEFg45hijk67MNO890",[int]$Length=7)
    
    $ofs=""
    [string]$newString=$source.ToCharArray() | Get-Random -count $length
    write-Output $NewString
}

#sample
#New-RandomString -length 9