PowerShell Syntax: compare and nest

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PowerShell uses so-called comparison operators for comparing values. Pipes can be used to pass different PowerShell commands to other commands.

compare

To compare certain values there are the following comparison operators.

Examples are:

-eq equal

-ne not equal

-gt greater than

-ge greater than or equal to

-lt less than

-le less than or equal to

we use"-gt" (greater than) in our next example:

Pipes (redirection)

By using the pipe symbol"|" several commands can be nested or redirected:

compare to the example dir, (Get-ChildItem)

Get-ChildItem c:\testordner | where-Object {$_.Length -gt 50KB}

shows files (dir) in the folder c:\testfolder larger than 50KB.

we get the following output:

Mode                LastWriteTime     Length Name
----                -------------     ------ ----
-a---        19.03.2013     18:32     381816 PsExec.exe
-a---        19.03.2013     18:32     105264 psfile.exe
-a---        19.03.2013     18:32     333176 PsGetsid.exe
-a---        19.03.2013     18:32     390520 PsInfo.exe
-a---        19.03.2013     18:32     468592 pskill.exe
-a---        19.03.2013     18:32     232232 pslist.exe
-a---        19.03.2013     18:32     183160 PsLoggedon.ex
-a---        19.03.2013     18:32     178040 psloglist.exe
-a---        19.03.2013     18:32     171608 pspasswd.exe
-a---        19.03.2013     18:32     167048 psping.exe
-a---        19.03.2013     18:32     169848 PsService.exe
-a---        19.03.2013     18:32     207664 psshutdown.ex
-a---        19.03.2013     18:32     187184 pssuspend.exe
-a---        19.03.2013     18:32      66582 Pstools.chm

Sort

If we want to sort the list by size, we need another pipe

Get-ChildItem c:\testordner | where-Object {$_.Length -gt 50KB} | Sort-Object Length

The output then looks like this:

Mode                LastWriteTime     Length Name
----                -------------     ------ ----
-a---        19.03.2013     18:32      66582 Pstools.chm
-a---        19.03.2013     18:32     105264 psfile.exe
-a---        19.03.2013     18:32     167048 psping.exe
-a---        19.03.2013     18:32     169848 PsService.exe
-a---        19.03.2013     18:32     171608 pspasswd.exe
-a---        19.03.2013     18:32     178040 psloglist.exe
-a---        19.03.2013     18:32     183160 PsLoggedon.exe
-a---        19.03.2013     18:32     187184 pssuspend.exe
-a---        19.03.2013     18:32     207664 psshutdown.exe
-a---        19.03.2013     18:32     232232 pslist.exe
-a---        19.03.2013     18:32     333176 PsGetsid.exe
-a---        19.03.2013     18:32     381816 PsExec.exe
-a---        19.03.2013     18:32     390520 PsInfo.exe
-a---        19.03.2013     18:32     468592 pskill.exe

So that the sorting recognizes the data type correctly, something can be helped:

If all file names should consist of numbers, Sort-Object would sort the names alphabetically: 1000 would then be smaller than 50 as an example.

The remedy is to assign the data type: Sort-Object { $_.Name.replace("stringpart","") -as [int] }

Data types, see: PowerShell Variables, Data Types and Objects.

Output

The formatting of the output can be customized with another pipe, so to get a list instead of the table view the command: Format-List can be used:

Get-ChildItem c:\testordner | where-Object {$_.Length -gt 50KB} | Sort-Object Length | Format-List
    Verzeichnis: C:\testordner
Name           : Pstools.chm
Length         : 66582
CreationTime   : 20.02.2013 17:22:50
LastWriteTime  : 19.03.2013 18:32:56
LastAccessTime : 20.02.2013 17:22:50
VersionInfo    :
File:             C:\testordner\Pstools.chm                 
InternalName:                 Original
Filename:                 File
Version:                 File
Description:                 
Product:                 
ProductVersion:                 
Debug:            False                 
Patched:          False                 
PreRelease:       False                
PrivateBuild:     False                 
SpecialBuild:     False                 
Language:
Name           : psfile.exe
Length         : 105264
CreationTime   : 20.02.2013 17:22:50
LastWriteTime  : 19.03.2013 18:32:54
LastAccessTime : 20.02.2013 17:22:50
VersionInfo    : 
File:             C:\testordner\psfile.exe                 
InternalName:     psfile                 
OriginalFilename: psfile.exe                 
FileVersion:      1.02                
FileDescription:  psfile                 
Product:          Sysinternals PsFile                 
ProductVersion:   1.02                 
Debug:            False                 
Patched:          False                 
PreRelease:       False                 
PrivateBuild:     False                 
SpecialBuild:     False                 
Language:         Englisch (Vereinigte Staaten).........

Example read event log:

For example, the event log can be read out on a remote computer, a pipe | can be used to search in it and another pipe | can be used to export the result to a csv file:

get-winevent -computername RemoteSystem -Logname System | where {$_.Message | findstr "zu suchen"} | Export-Csv c:\temp\sucheimEventlog.csv
positive Bewertung({{pro_count}})
Rate Post:
{{percentage}} % positive
negative Bewertung({{con_count}})

THANK YOU for your review!


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