Show Type of Event in PowerShell - powershell

Question

I need to create a script in which will ask for a type of events to display (For example: system). The script will show on screen the events of the selected type grouped by the event id. These will be shown on the screen ordered by the number of events of the same.
I tried creating the script and these are my results. I would like to know if there is any mistake on it.
cls
$eventType = Read-host "Introduce one kind of event"
try { Get-EventLog -LogName $eventType | Group-Object 'InstanceID' | Sort-Object -Property InstanceID -Descending -ErrorAction Stop}
catch { Write-Output "unrecognizable event" }

Answer 1

I got your script to work by breaking the command for user input into its own variable.
$LogName = Read-host "Introduce one kind of event"
$eventType = try { Get-EventLog -LogName $LogName | Group-Object 'InstanceID' | Sort-Object -Property InstanceID -Descending -ErrorAction Stop} catch { Write-Output "unrecognizable event" }
$eventType

Answer 2

So after reading your code pre edit there is a couple of things that I would like to highlight;
1, You had pasted your code as a single line, this would have not executed as it would have considered everything else after cls as arguments. New lines and ; indicate end of command.
As a single line you would have to seperate your commands using ;
cls; $eventType = Read-host "Introduce one kind of event"; try { Get-EventLog -LogName $eventType | Group-Object 'InstanceID' | Sort-Object -Property InstanceID -Descending -ErrorAction Stop} catch { Write-Output "unrecognizable event" }
However I do advise breaking your code into multiple lines.
2, To order by the number of instances (ordered by the number of events of the same) you would need to modify your sort-object:
cls
$eventType = Read-host "Introduce one kind of event"
try { Get-EventLog -LogName $eventType | Group-Object 'InstanceID' | Sort-Object -Property Count -Descending -ErrorAction Stop}
catch { Write-Output "unrecognizable event" }
The initial object Get-EventLog is destroyed and replaced by the Group-Object object. The property you would then want to sort-object by is Count, you can inspect the properties of an object by using get-member.