Useful PowerShell Commands

usefulPowerShellCommands_1.ps1

# Get powershell version
$PSVersionTable.PSVersion

# Get .NET version source: http://stackoverflow.com/questions/3487265/powershell-to-return-versions-of-net-framework-on-a-machine
Get-ChildItem 'HKLM:\SOFTWARE\Microsoft\NET Framework Setup\NDP' -recurse |
Get-ItemProperty -name Version -EA 0 |
Where { $_.PSChildName -match '^(?!S)\p{L}'} |
Select PSChildName, Version

# Get windows version
[System.Environment]::OSVersion.Version

# Don't truncate long fields when powershell returns content
... | format-table -autosize

# Get System Restore points (Only on Client OSs)
get-computerrestorepoint | format-table -autosize

# Create System Restore point
checkpoint-computer -description "Installing questionable software"

# When viewing multiple files with different file extensions, group by file extension (i.e. when you cleaning your desktop)
ls | group Extension | sort Count -Descending

# Find number of lines in a file (cat)
get-content file.txt | measure-object

# Find directories that are empty
Get-ChildItem -Recurse -Directory | Where-Object {$_.GetFiles().Count -eq 0}

# Get CPU Load
Get-WmiObject win32_processor | select LoadPercentage | fl

# Get processes by wmi and searching for processes by command arguments
Get-WmiObject win32_process -filter "name = '$processName'" -Property commandline, processid `
                        | where { $_.commandline -match $commandLineMatch } `
                        | select processid

# For each foreach for-each example
Get-Process | ForEach-Object {Write-Host $_.name -foregroundcolor cyan}

# start a process with arguments
$args = "/v:1.0 /nowait"
$exe ="notepad.exe"
start-process $exe $args

# Prompt the user before commiting an action
-whatif or -confirm

#Exit or kill the currently executing script and exit powershell
Exit

# break wil break out of function or script
Break

# Access arguments in a function and pass arguments to function (spaces)
&doStuff 1 5

function doStuff
{
  return args[0] + args[1];
}

# View your command history (first 32 by defult out of 64)
get-history 
# View first 32 commands
get-hisotry 32 -count 32

# Set maximum history commands saved
$MaximumHistoryCount = 500

# Enable remote access via WinRM (Windows Remote Mangement)
# http://technet.microsoft.com/en-us/magazine/ff700227.aspx
get-service winrm # Needs to be running
enable-psremoting -force
winrm s winrm/config/client '@{TrustedHosts="*"}' # Allow anyone to access

# Client remote commands
$a = new-pssession -computername dev-portal
get-pssession
enter-pssession -id 1 # enter-pssession $a

# Replace file content (only for V3)
(gc c:\temp\test.txt).replace('[MYID]','MyValue')|sc c:\temp\test.txt

# Escaping characters
# Single quotes - double single quotes
"he'll'o".Replace('he''ll''o','hi')

# Find difference between two dates
$startDate = get-date
$endDate = [datetime]"01/01/2016 00:00"
new-timespan -start $startDate -end $endDate

# Get current directory of currently running script
$scriptPath = $MyInvocation.MyCommand.Path
$dir = split-path $scriptPath

# Pass arguments to remote commands
$arg1 = "x:\\sites\site1"
$a = new-pssession -computer remotename
invoke-command -session $a -script {param($whatyouwant) cd $whatyouwant} -Args $arg1

# Check for null
$a = $null
if ($a) {
  # NOT NULL
} else {
  # NULL
}

# Map drive
new-psdrive -name "k" -psprovider FileSystem -Root "\\api-01\c$" -Persist

# Read a JSON file
(Get-Content JsonFile.JSON) -join "`n" | ConvertFrom-Json

# Turn PS-Drive path into UNC path for .NET file operation classes
(Resolve-Path $file).ProviderPath
# i.e. - (Resolve-Path "nodeBox:\sites\node1").ProviderPath --> \\node-01\sites\node1

# Copy file with buffer and progress bar
# http://stackoverflow.com/questions/2434133/progress-during-large-file-copy-copy-item-write-progress
function Copy-File {
    param( [string]$from, [string]$to)
    $ffile = [io.file]::OpenRead($from)
    $tofile = [io.file]::OpenWrite($to)
    Write-Progress -Activity "Copying file" -status "$from -> $to" -PercentComplete 0
    try {
        [byte[]]$buff = new-object byte[] 4096
        [int]$total = [int]$count = 0
        do {
            $count = $ffile.Read($buff, 0, $buff.Length)
            $tofile.Write($buff, 0, $count)
            $total += $count
            if ($total % 1mb -eq 0) {
                Write-Progress -Activity "Copying file" -status "$from -> $to" `
                   -PercentComplete ([int]($total/$ffile.Length* 100))
            }
        } while ($count -gt 0)
    }
    finally {
        $ffile.Dispose()
        $tofile.Dispose()
    }
}