The Wiert Corner – irregular stream of stuff

Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

  • My badges

  • Twitter Updates

  • My Flickr Stream

  • Pages

  • All categories

  • Enter your email address to subscribe to this blog and receive notifications of new posts by email.

    Join 1,651 other followers

Archive for the ‘PowerShell’ Category

DTW-DanWard/PowerShell-Beautifier: A whitespace reformatter and code cleaner for Windows PowerShell and PowerShell Core

Posted by jpluimers on 2019/07/23

Interesting tool: DTW-DanWard/PowerShell-Beautifier: A whitespace reformatter and code cleaner for Windows PowerShell and PowerShell Core

–jeroen

via: [WayBack] Is there a PowerShell code formatter / pretty printer? – Stack Overflow

Posted in CommandLine, Development, PowerShell, PowerShell, Scripting, Software Development | Leave a Comment »

PowerShell: Format-Table to show all columns/members

Posted by jpluimers on 2019/07/18

I’m not even sure if I’ve posted this before, but I always forget how to show all members (or columns) using Format-Table.

It’s dead easy: -Property *

Get-ChildItem | Format-Table -Property *

Later I found out this is equivalent with the shorter version where you omit the -Property part which I wrote about in [WayBackPowerShell: when Format-Table -AutoSize displays only 10 columns and uses the width of the console when redirecting to file.

So you can shorten the above to:

Get-ChildItem | Format-Table *

It has way more columns than this:

Get-ChildItem | Format-Table

The extra members in both marked with *:

  • PSPath
  • PSParentPath
  • PSChildName
  • PSDrive
  • PSProvider
  • PSIsContainer
  • BaseName
  • Mode *
  • Name *
  • FullName
  • Parent
  • Exists
  • Root
  • Extension
  • CreationTime
  • CreationTimeUtc
  • LastAccessTime
  • LastAccessTimeUtc
  • LastWriteTime *
  • LastWriteTimeUtc
  • Attributes

The odd thing: one property fails in the -Property * table:

  • Length

I tracked this down to how -Property * works: it takes the first entry in the list. If that is not a file, then it has no Length property: [WayBackpowershell – Measure-Object : The property “length” cannot be found in the input for any objects – Stack Overflow.

Note that for a GUI version, you can replace Format-Table with Out-GridView. See

-jeroen.

Posted in CommandLine, Development, PowerShell, PowerShell, Scripting, Software Development | Leave a Comment »

PowerShell: the issues you bump into when using Get-Counter and Measure-Object aggregation

Posted by jpluimers on 2019/07/17

Single process data

You can get many process properties using , for instance the total running time in minutes [WayBack] Get-Process:

New-TimeSpan -Start (Get-Process "devenv").StartTime | Select-Object -ExpandProperty "TotalMinutes"

Actually, the it matches multiple process instances, then you need to aggregate, for instance using this:

Get-Process "cmd" | ForEach-Object { New-TimeSpan -Start $_.StartTime } | Measure-Object -Property "TotalMinutes" -Sum | Select-Object -ExpandProperty "Sum"

If you want to see which properties are available, then use either of these:

Get-Process | Select-Object * | Out-GridView
Get-Process | Get-Member

Getting aggregated process CPU usage times

Lets start getting the total CPU time of all processes by using Get-Process which – without arguments – returns data for all processes it has access to:

PS C:\Users\Developer> Get-Process | Measure-Object -Property CPU -Sum

You’d think this gives only the sum. Wrong:

Count : 80
Average :
Sum : 2410.5625
Maximum :
Minimum :
Property : CPU

Ensure you get data for all processes

And you need it with an Administrative UAC token in order to get all processes on the system. It doesn’t show many more processes, but a lot more CPU time since boot:

Count : 83
Average :
Sum : 6078.125
Maximum :
Minimum :
Property : CPU

Showing one aggregate

So how to get rid of [WayBack] Measure-Object showing all aggregates?

The only stable solution I found is to expand that into | Measure-Object -Property CPU -Sum | Select-Object -ExpandProperty Sum which I found in the answer by davidhigh at [WayBack] Listing processes by CPU usage percentage in powershell – Stack Overflow and got me this by using [WayBack] Select-Object.

Note you have to use -ExpandProperty as just -Propertywill not cut it as you get an empty result (I think this has to do with Sum being a nullable type: Sum Property System.Nullable[double]):

PS C:\Windows\system32> Get-Process | Measure-Object -Property CPU -Sum | Select-Object -Property Sum
PS C:\Windows\system32> Get-Process | Measure-Object -Property CPU -Sum | Select-Object -ExpandProperty Sum
6126.40625

CPU % is hard

You’d think a CPU % is an easy thing to measure as it has been available in the Task Manager for such a long time, but it’s harder to determine than for instance process memory. Let me try to explain that (please post comments when it is unclear).

For process memory, you can measure it at the current instant: if you freeze the CPU, you can count the number of bytes used by the process.

For relative CPU usage however, you need to measure how a process executes over time. During that time, CPU usage may (or will) vary a little bit, so you need to measure over a little time-delta. If CPU core frequencies vary over time, you need to adjust for that so it gets even more difficult. Two links with a bit more background information on this:

I think the above difference is the reason that Get-Process doesn’t return a CPU percentage.

Performance Counters using Get-Counter

Instead, you can use [WayBackGet-Counter to get processor CounterSampleslike this:

(Get-Counter '\Process(*)\% Processor Time').CounterSamples

It gets you the % Processor Time which is the percentage of CPU determined by a CPU [WayBackHardware performance counter.

Filtering results

If you want this for a specific process, you first need to find out which processes exist. You can do that by getting the unique InstanceName property values by using [WayBack] Sort-Object:

(Get-Counter '\Process(*)\% Processor Time').CounterSamples | Select-Object -Property InstanceName | Sort-Object -Property InstanceName -Unique

(Here you do not need the -ExpandProperty on Select-Objectas the -Property suffices)

Special InstanceName values

There are always entries with InstanceName having values _total and idle:

(Get-Counter '\Process(*)\% Processor Time').CounterSamples | Where-Object {$_.InstanceName -eq "_total" }
(Get-Counter '\Process(*)\% Processor Time').CounterSamples | Where-Object {$_.InstanceName -eq "idle" }

You can even get both at the same time by using the -or operator with [WayBackWhere-Object:

(Get-Counter '\Process(*)\% Processor Time').CounterSamples | Where-Object {($_.InstanceName -eq "_total") -or ($_.InstanceName -eq "idle") }

Since the outputs are CPU core based, and sampled over time, they can be above 100%, heck even above the 100% * amount-of-CPU-cores as seen on a 2-core CPU system:

Path                                                InstanceName  CookedValue
----                                                ------------  -----------
\\w81entx64vs2015\process(idle)\% processor time    idle          186.168932138452
\\w81entx64vs2015\process(_total)\% processor time  _total        200.016208082634

You see that the CookedValue is what you’re after. If you just want the value for one instance, just use the -ExpandProperty trick shown above:

(Get-Counter '\Process(*)\% Processor Time').CounterSamples | Where-Object {$_.InstanceName -eq "_total" } | Select-Object -ExpandProperty CookedValue

Accommodating for multi-instance processes

(Get-Counter '\Process(*)\% Processor Time').CounterSamples | Where-Object {$_.InstanceName -eq "svchost" } | Select-Object -ExpandProperty CookedValue

This gets you a list like this:

PS C:\Windows\system32> (Get-Counter '\Process(*)\% Processor Time').CounterSamples | Where-Object {$_.InstanceName -eq "svchost" } | Select-Object -ExpandProperty CookedValue
0
0
...
0
0

For that, you need to aggregate by using Measure-Object like described in the Get-Process section:

PS C:\Windows\system32> (Get-Counter '\Process(*)\% Processor Time').CounterSamples | Where-Object {$_.InstanceName -eq "svchost" } | Measure-Object -Property CookedValue -Sum | Select-Object -ExpandProperty Sum
0

A more elaborate example of aggregating is at [Archive.isExportPerfomanceCountersHelpers.ps1.

Aggregated output usually works

This works for a single-instance process as well:

(Get-Counter '\Process(*)\% Processor Time').CounterSamples | Where-Object {$_.InstanceName -eq "lsass" } | Measure-Object -Property CookedValue -Sum | Select-Object -ExpandProperty Sum

Example output:

PS C:\Windows\system32> (Get-Counter '\Process(*)\% Processor Time').CounterSamples | Where-Object {$_.InstanceName -eq "lsass" } | Measure-Object -Property CookedValue -Sum | Select-Object -ExpandProperty Sum
0

The dreaded error

The above often works, but sometimes you get an error, often even earlier in the process.

The error is always like Get-Counter : The data in one of the performance counter samples is not valid. View the Status property for each PerformanceCounterSample object to make sure it contains valid data.:

PS C:\Windows\system32> (Get-Counter '\Process(*)\% Processor Time').CounterSamples | Where-Object {$_.InstanceName -eq "lsass" } | Measure-Object -Property CookedValue -Sum | Select-Object -ExpandProperty Sum
Get-Counter : The data in one of the performance counter samples is not valid. View the Status property for each PerformanceCounterSample object to make sure it contains valid data.
At line:1 char:2
+ (Get-Counter '\Process(*)\% Processor Time').CounterSamples | Where-Object {$_.I ...
+  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidResult: (:) [Get-Counter], Exception
    + FullyQualifiedErrorId : CounterApiError,Microsoft.PowerShell.Commands.GetCounterCommand

0

It took me a while to figure this out, but the root cause is that in-between Get-Counter retrieving the hardware process counters and processing the values, the CPU continues executing thereby changing some of the values. For instance, processes can quit (the CPU is not aware of processes, so binding CPU thread information from the hardware process counters to logical processes can fail in that step).

These links helped me tremendously as the -ErrorAction SilentlyContinue is not documented by Microsoft at Get-Counter:

Summary

Always use a construct like this to search for CPU usages on one or more processes named powershell:

(Get-Counter '\Process(*)\% Processor Time' -ErrorAction SilentlyContinue).CounterSamples | Where-Object {$_.InstanceName -eq "powershell" } | Measure-Object -Property CookedValue -Sum | Select-Object -ExpandProperty Sum

–jeroen

Posted in CommandLine, Development, PowerShell, PowerShell, Scripting, Software Development | Leave a Comment »

PowerShell: $args variable outer scope has command-line arguments – about_Automatic_Variables | Microsoft Docs

Posted by jpluimers on 2019/07/16

I always forget the exact syntax for getting command-line arguments to PowerShell. It’s the $args implicit array variable:

–jeroen

Posted in CommandLine, Development, PowerShell, PowerShell, Scripting, Software Development | Leave a Comment »

Run cmd as elevated user (via: windows – How to run batch file command with elevated permissions? – Super User)

Posted by jpluimers on 2019/03/13

Based on [WayBack] windows – How to run batch file command with elevated permissions? – Super User:

powershell -command "Start-Process cmd.exe -Verb runas"

This works better than "runas /user:administrator cmd.exe" as that forces to use the specific Administrator account, whereas the PowerShell way allows you to specify the actual account during elevation.

–jeroen

Posted in Batch-Files, CommandLine, Console (command prompt window), Development, Power User, PowerShell, PowerShell, Scripting, Software Development, Windows | Leave a Comment »

 
%d bloggers like this: