CODEWITHSUNDEEP
powershellsyntax
MKANET
MKANET

Reputation: 663

Where-Object cmdlet syntax

I'm trying to learn how to use Where-Object correctly in the below command-lines to display all processes larger than 20 megabytes.

get-process | Select-Object Name, @{Name="Private Memory (MB)"; Expression={$_.privatememorysize / 1mb}} |
    Where-Object {"Private Memory (MB)" -gt 20} |
    Sort-Object "Private Memory (MB)" -Descending |
    format-table -autosize

I am able to kind of do it in the below command-line. However, I don't want to specify it using 20971520 bytes. I would rather like to specify it in megabytes. If that's not possible (or the command-line would get too complex), then I'd just like the output to show all processes larger than 20 MB; even if I have to specify it using bytes:

get-process | Select-Object Name, @{Name="Private Memory (MB)"; Expression={$_.privatememorysize / 1mb}} |
    where-object {$_.privatememorysize -gt 20971520} |
    Sort-Object "Private Memory (MB)" -Descending |
    format-table -autosize

Upvotes: 1

Views: 799

Answers (2)

Anthony Neace
Anthony Neace

Reputation: 26023

You can specify sizes literally in PowerShell:

PS C:\> 1KB
1024
PS C:\> 1MB
1048576
PS C:\> 1GB
1073741824

So you can use those literally in your code when you want to perform a mathematical operation. So if all you wanted to do was to replace that literal, go for it:

$myProcesses = get-process | 
where-object { $_.privatememorysize -gt 20MB } | 
select-object name, @{ Name = "Private Memory (MB)"; Expression = {$_.privatememorysize / 1MB}} |
Sort-object "Private Memory (MB)" -Descending

A note: you'll probably only want to use format-table on an object when it is ready to be output to be read by a user. So in this case, once you're ready to output this to the screen you could simply do $myProcesses | format-table -autosize. If you're doing this from the command line and simply want to see the results ASAP, then don't even bother with the variable and format it like you described.

Upvotes: 1

Benjamin Hubbard
Benjamin Hubbard

Reputation: 2917

Change

where-object {"Private Memory (MB)" -gt 20}

to

where-object {$_."Private Memory (MB)" -gt 20}

As in

get-process | 
    Select-Object Name, @{Name="Private Memory (MB)"; Expression={$_.privatememorysize / 1mb}} | 
    Where-Object {$_."Private Memory (MB)" -gt 20} | 
    Sort-Object "Private Memory (MB)" -Descending | 
    format-table -autosize

The reason you can just use 20 (vs 20mb) in your Where-Object expression is because you already specified the unit of measure in your select statement. In fact, if you use 20971520, it will think you mean 20971520 MB.

Upvotes: 1

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