Extract columns from text based table output - powershell

Question

qfarm /load command shows me the load from my servers.
Output:
PS> qfarm /load
Server Name Server Load Load Throttling Load Logon Mode
-------------------- ----------- -------------------- ------------------
SERVER-01 400 0 AllowLogons
SERVER-02 1364 OFF AllowLogons
SERVER-03 1364 OFF AllowLogons
SERVER-04 1000 0 AllowLogons
SERVER-05 700 0 AllowLogons
SERVER-06 1200 0 AllowLogons
I need to display only first column (Server Name) and the second one (Server Load) and loop through them, in order to make some logic later, but it seems the powershell doesn't see it as object with properties:
PS> qfarm /load | Select -ExpandProperty "Server Name"
Select-Object : Property "Server Name" cannot be found.
Is there any other possibility, like a table or something?

Answer 1

One way to do this is to build objects out of the command's output. Tested the following:
#requires -version 3
# sample data output from command
$sampleData = #"
Server Name Server Load Load Throttling Load Logon Mode
-------------------- ----------- -------------------- ------------------
SERVER-01 400 0 AllowLogons
SERVER-02 1364 OFF AllowLogons
SERVER-03 1364 OFF AllowLogons
SERVER-04 1000 0 AllowLogons
SERVER-05 700 0 AllowLogons
SERVER-06 1200 0 AllowLogons
"# -split "`n"
$sampleData | Select-Object -Skip 2 | ForEach-Object {
$len = $_.Length
[PSCustomObject] #{
"ServerName" = $_.Substring(0, 22).Trim()
"ServerLoad" = $_.Substring(22, 13).Trim() -as [Int]
"LoadThrottlingLoad" = $_.Substring(35, 22).Trim()
"LogonMode" = $_.Substring(57, $len - 57).Trim()
}
}
In your case, you should be able to replace $sampleData with your qfarm load command; e.g.:
qfarm /load | Select-Object -Skip 2 | ForEach-Object {
...
Of course, this is assuming no blank lines in the output and that my column positions for the start of each item is correct.
PowerShell version 2 equivalent:
#requires -version 2
function Out-Object {
param(
[Collections.Hashtable[]] $hashData
)
$order = #()
$result = #{}
$hashData | ForEach-Object {
$order += ($_.Keys -as [Array])[0]
$result += $_
}
New-Object PSObject -Property $result | Select-Object $order
}
# sample data output from command
$sampleData = #"
Server Name Server Load Load Throttling Load Logon Mode
-------------------- ----------- -------------------- ------------------
SERVER-01 400 0 AllowLogons
SERVER-02 1364 OFF AllowLogons
SERVER-03 1364 OFF AllowLogons
SERVER-04 1000 0 AllowLogons
SERVER-05 700 0 AllowLogons
SERVER-06 1200 0 AllowLogons
"# -split "`n"
$sampleData | Select-Object -Skip 2 | ForEach-Object {
$len = $_.Length
Out-Object `
#{"ServerName" = $_.Substring(0, 22).Trim()},
#{"ServerLoad" = $_.Substring(22, 13).Trim() -as [Int]},
#{"LoadThrottlingLoad" = $_.Substring(35, 22).Trim()},
#{"LogonMode" = $_.Substring(57, $len - 57).Trim()}
}

Answer 2

You can easily convert your table to PowerShell objects using the ConvertFrom-SourceTable cmdlet from the PowerShell Gallery:
$sampleData = ConvertFrom-SourceTable #"
Server Name Server Load Load Throttling Load Logon Mode
-------------------- ----------- -------------------- ------------------
SERVER-01 400 0 AllowLogons
SERVER-02 1364 OFF AllowLogons
SERVER-03 1364 OFF AllowLogons
SERVER-04 1000 0 AllowLogons
SERVER-05 700 0 AllowLogons
SERVER-06 1200 0 AllowLogons
"#
And than select your columns like:
PS C:\> $SampleData | Select-Object "Server Name", "Server Load"
Server Name Server Load
----------- -----------
SERVER-01 400
SERVER-02 1364
SERVER-03 1364
SERVER-04 1000
SERVER-05 700
SERVER-06 1200
For details see: ConvertFrom-SourceTable -?
The ConvertFrom-SourceTable cmdlet is available for download at the PowerShell Gallery and the source code from the GitHub iRon7/ConvertFrom-SourceTable repository.

Answer 3

Command-line utilities return their outputs as a string array. This should work:
qfarm /load | ForEach-Object { $_.Substring(0,33) }

Answer 4

I have answered something very similar to this in the past. I have a larger function for this but a simplified on work on left aligned string table just as you have shown in you example. See the linked answer for more explanation.
function ConvertFrom-LeftAlignedStringData{
param (
[string[]]$data
)
$headerString = $data[0]
$headerElements = $headerString -split "\s{2,}" | Where-Object{$_}
$headerIndexes = $headerElements | ForEach-Object{$headerString.IndexOf($_)}
$results = $data | Select-Object -Skip 2 | ForEach-Object{
$props = #{}
$line = $_
For($indexStep = 0; $indexStep -le $headerIndexes.Count - 1; $indexStep++){
$value = $null # Assume a null value
$valueLength = $headerIndexes[$indexStep + 1] - $headerIndexes[$indexStep]
$valueStart = $headerIndexes[$indexStep]
If(($valueLength -gt 0) -and (($valueStart + $valueLength) -lt $line.Length)){
$value = ($line.Substring($valueStart,$valueLength)).Trim()
} ElseIf ($valueStart -lt $line.Length){
$value = ($line.Substring($valueStart)).Trim()
}
$props.($headerElements[$indexStep]) = $value
}
New-Object -TypeName PsCustomObject -Property $props
}
return $results
}
$qfarmOutput = qfarm /load
ConvertFrom-LeftAlignedStringData $qfarmOutput | select "Server Name","Server Load"
This approach is based on the position of the header fields. Nothing is hardcoded and it is all custom built based on those indexes and field names. Using those $headerIndexes we carve up every line and place the results, if present, into its respective column. There is logic to ensure that we don't try and grab any part of the string that might not exist and treat the last field special.
Results
Server Name Server Load
----------- -----------
SERVER-01 400
SERVER-02 1364
SERVER-03 1364
SERVER-04 1000
SERVER-05 700
SERVER-06 1200