Useful PowerShell command-line operations

The commands below are a small but growing list of powershell one-liners I've used (and when I remember to take note). Note that this may not be the best and almost certainly isn't the only way in most cases.

Each command-line can be copied and pasted at a PowerShell command prompt, or you can use the commands as part of a PS1 script file if you prefer.


Show help on commands such as 'if', regular expressions etc
help about*

Show help about about_Automatic_variables such as $_ $DebugPreference $OFS
help about_Automatic_variables

Run a command and pipe the results to a variable
cscript.exe //nologo script.wsf | Set-Variable -name scriptResults

Run a command and set a variable with the output
$scriptResults = cscript.exe //nologo script.wsf

Run a command and set a variable with the output using the call operator
$scriptResults = & cscript.exe //nologo script.wsf

Filter an object based on an array of strings
$array = "a", "b"; write-output a b c d | select-string -pattern $array -simpleMatch

Reformat today's date to YYYYMMDD
$today = [DateTime]::Now.ToString("yyyyMMdd")

Find local disks except C: using powershell and output to CSV
Get-WmiObject -Namespace root\cimv2 -ComputerName %server% -Query "SELECT * from Win32_LogicalDisk WHERE FileSystem='NTFS' AND Description = 'Local Fixed Disk' AND Name != 'C:'" | export-csv c:\disk.csv

Use the VI Toolkit Powershell snap-in to query for snapshots
Get-VM | Get-Snapshot | export-csv -path c:\temp\VMsnapshots.csv

Use the VI Toolkit Powershell snap-in to query for snapshot information
Get-VM | Get-Snapshot | foreach-object {$out= $_.VM.Name + "," + $_.Name + "," + $_.Description + "," + $_.PowerState; $out}

Start a remote process using Powershell/WMI
$computer = "."; ([WMICLASS]"\\$computer\root\CIMv2:win32_process").Create("notepad.exe")

Find remote processes and the command-line parameters with PowerShell
Get-WmiObject win32_process | Format-Table ExecutablePath,Caption,CommandLine,CreationDate,WorkingSetSize,ProcessId

Generate a password 10 characters in length, at least 5 punctuation marks
[void] [System.Reflection.Assembly]::LoadWithPartialName("System.Web") ; [System.Web.Security.Membership]::GeneratePassword(10,5)

Format a date to XML XSD:dateTime
$Now = [DateTime]::Now.ToString("yyyy-MM-ddTHH:mm:ss")

Check if the given variable is an object
if ($variable -is [object]) {}

Check which network connections (drive mappings) a 2003 computer has
get-WMIObject -computerName "$env:computername" -class win32_logicaldisk -property ProviderName, DeviceID -filter "DriveType=4" | Format-List -property ProviderName, DeviceID

See whether an IP can be resolved to a host name
[System.net.Dns]::GetHostEntry($IP)

See whether a host name can be resolve to an IP
$ip = & { trap {continue}; [System.net.Dns]::GetHostAddresses($computer) }

View the datastore information for the available storage
get-vc -server $server ; Get-Datastore

Check if a file or path exists or not
test-path -path $path ; if (!(test-path -path $path)) {write-output "$path does not exist"}

Use psexec to run a powershell command remotely and report to stdout (eg query 'remote' event logs in this example)
psexec \\machine /s cmd /c "echo. | powershell . get-eventlog -newest 5 -logname application | select message"



Wayne's World of IT (WWoIT), Copyright 2008 Wayne Martin.