How to find the Windows version from the PowerShell command line

Unfortunately most of the other answers do not provide information specific to Windows 10.

Windows 10 has versions of its own: 1507, 1511, 1607, 1703, etc. This is what winver shows.

Powershell:
(Get-ItemProperty "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion").ReleaseId

Command prompt (CMD.EXE):
Reg Query "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion" /v ReleaseId

See also related question on superuser.

As for other Windows versions use systeminfo. Powershell wrapper:

PS C:\> systeminfo /fo csv | ConvertFrom-Csv | select OS*, System*, Hotfix* | Format-List


OS Name             : Microsoft Windows 7 Enterprise
OS Version          : 6.1.7601 Service Pack 1 Build 7601
OS Manufacturer     : Microsoft Corporation
OS Configuration    : Standalone Workstation
OS Build Type       : Multiprocessor Free
System Type         : x64-based PC
System Locale       : ru;Russian
Hotfix(s)           : 274 Hotfix(s) Installed.,[01]: KB2849697,[02]: KB2849697,[03]:...

Windows 10 output for the same command:

OS Name             : Microsoft Windows 10 Enterprise N 2016 LTSB
OS Version          : 10.0.14393 N/A Build 14393
OS Manufacturer     : Microsoft Corporation
OS Configuration    : Standalone Workstation
OS Build Type       : Multiprocessor Free
System Type         : x64-based PC
System Directory    : C:\Windows\system32
System Locale       : en-us;English (United States)
Hotfix(s)           : N/A

1. To get the Windows version number, as Jeff notes in his answer, use:

   [Environment]::OSVersion
   

   It is worth noting that the result is of type [System.Version], so it is possible to check for, say, Windows 7/Windows Server 2008 R2 and later with

   [Environment]::OSVersion.Version -ge (new-object 'Version' 6,1)
   

   However this will not tell you if it is client or server Windows, nor the name of the version.

2. Use WMI's Win32_OperatingSystem class (always single instance), for example:

   (Get-WmiObject -class Win32_OperatingSystem).Caption
   

   will return something like

   Microsoft® Windows Server® 2008 Standard

Since you have access to the .NET library, you could access the OSVersion property of the System.Environment class to get this information. For the version number, there is the Version property.

For example,

PS C:\> [System.Environment]::OSVersion.Version

Major  Minor  Build  Revision
-----  -----  -----  --------
6      1      7601   65536

Details of Windows versions can be found here.