Powershell search by single and multiple keyword - powershell

Question

I have some commands below that do not give any output when looking for specific keywords in Windows Logs using PowerShell.
Get-WinEvent -FilterHashtable #{LogName="Application"} | Select-String "Information"
However, if I only run Get-WinEvent -FilterHashtable #{LogName="Application"}, there are many entries with Information keyword. Select-String -pattern "Information" also does not work.
Ideally I'd like to search for multiple keywords in the above scenario.

Answer 1

You need to do:
Get-WinEvent -FilterHashtable #{LogName="Application"} | ? { $_.leveldisplayname -eq 'Information' }
The Information you're looking for is a property of the object. The Get-WinEvent cmdlet returns a collection of objects, so you need to add the Where-Object or ? to filter on the LevelDisplayName object property.
To answer your new questions:
The leveldisplayname is going to be Information, Error or Warning. You can add either of these or use logic to combine them. In order to search for keywords in a message, using a regex is probably the best approach:
Get-WinEvent -FilterHashtable #{LogName="Application"} | ? message -imatch "keyword1"
To search multiple keywords, you can modify the regex using the OR | operator:
Get-WinEvent -FilterHashtable #{LogName="Application"} | ? message -imatch "keyword1|keyword2|foo|bar"
If you wanted to search for all Error messages containing "foo" or "bar" you could do;
Get-WinEvent -FilterHashtable #{LogName="Application"} | ? { ($_.message -imatch "foo|bar") -and ($_.leveldisplayname -eq 'Error') }