Cannot extract PSVersion string from $PSVersionTable - string

Question

I have the following output :
PS> $PSVersionTable
Name Value
---- -----
CLRVersion 2.0.50727.8806
BuildVersion 6.1.7601.17514
PSVersion 2.0
WSManStackVersion 2.0
PSCompatibleVersions {1.0, 2.0}
SerializationVersion 1.1.0.1
PSRemotingProtocolVersion 2.1
I'd like to get PSVersion value as a string like this into a variable : 2.0
So I tried this but it's not what I want :
PS> $PSVersionTable.PSVersion
Major Minor Build Revision
----- ----- ----- --------
2 0 -1 -1
and these commands :
EDIT0 : I had copied'n'pasted the wrong line but still the string concatenation didn't work :
PS> $myVariable = $PSVersionTable.PSVersion.Major + "." + $PSVersionTable.PSVersion.Minor
Cannot convert value "." to type "System.Int32". Error: "Input string was not in a correct format."
At line:1 char:48
+ $myVariable = $PSVersionTable.PSVersion.Major + <<<< "." + $PSVersionTable.PSVersion.Minor
+ CategoryInfo : NotSpecified: (:) [], RuntimeException
+ FullyQualifiedErrorId : RuntimeException
PS> $PSVersionTable | Select-Object PSVersion
PSVersion
---------
PS> $PSVersionTable | Get-Item PSVersion
Get-Item : The input object cannot be bound to any parameters for the command either because the command does not take pipeline input or the input and its properties do
not match any of the parameters that take pipeline input.
At line:1 char:27
+ $PSVersionTable | Get-Item <<<< PSVersion
+ CategoryInfo : InvalidArgument: (System.Collections.Hashtable:Hashtable) [Get-Item], ParameterBindingException
+ FullyQualifiedErrorId : InputObjectNotBound,Microsoft.PowerShell.Commands.GetItemCommand
I'm a powershell rookie, can you help me ?

Answer 1

You can use the .ToString() method on the PSVersion key's value.
$MyVariable = $PSVersionTable.PSVersion.ToString()
Or:
$MyVariable = $PSVersionTable[ "PSVersion" ].ToString()
Note: The different syntax is because $PSVersion is a hash table or a dictionary object. PowerShell lets you use either syntax. Your executing the method on the value that's returned.
$MyVariable will be a string like "2.0". I double checked in version 5.1 and got "5.1.19041.546". If you want to isolate just the major version you can do it like:
$MyVariable = $PSVersionTable.PSVersion.Major
But this won't give you the minor point version.
You could also do something like:
$PSVersionTable.PSVersion.Major,$PSVersionTable.PSVersion.Minor -join "."
This will return "5.1" in my case. So, just major & minor versions but dropping build and revision information. It works by formatting the 2 values into an array and joining them into a string on a "."
Note regarding your question:
The first error is due to PowerShell's type conversion system. This is a little more complex to explain here, but PowerShell will attempt to convert data types to complete operations. It's intuitive but not perfect, and in this case it can't convert the "." to a number. One thing to point out is the tendency to convert the right side to the type of the left. Below would work.
$PSVersionTable.PSVersion.Major.ToString() + "." + $PSVersionTable.PSVersion.Minor
Above manually converts the left to a string so there is no trouble concatenating with ".", when the second "+" is evaluated the Right side is easily converted from [Int32] to [String], so it will work.
In this case I would prefer to use casting like:
[String]$PSVersionTable.PSVersion.Major + "." + $PSVersionTable.PSVersion.Minor
Effectively this is the same, but I prefer it from a syntax perspective.
The select command doesn't work because you are sending the hash table down the pipe and technically there is no "PSVersion" property to select. A correction to that might look something like:
$PSVersionTable.GetEnumerator() |
Where-Object{ $_.Name -eq "PSVersion" } |
Select-Object value
Obviously this is less convenient than other solutions, but I included it for illustration.
The third problem is just not a correct command or syntax. Get-Item cannot take the $PSVerrsionTable hashtable as input, piped or otherwise.