PowerShell: What kind of keyword ist env: ? Meaning of such a keyword?

Question

For to display all environmental variables in PowerShell one uses:

Get-ChildItem env:

What is 'env:'?

It clear to me that it is some abbreviation for "environment". But what kind of abbreviation? What's the meaning of the colon at the end?

Answer 1

Your query is defined in the PowerShell help files:

About Automatic Variables:

https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_automatic_variables?view=powershell-7.1

$env is a virtual drive for the above. Easily seen via the below and its purpose to allow access to the above:

# These are treated as normal filesystem drives, and you can create custom ones.
Get-PSDrive
<#
Name     Used (GB) Free (GB) Provider    Root               CurrentLocation
----     --------- --------- --------    ----               ---------------
Alias                        Alias                                         
C             5.04     34.83 FileSystem  C:\                        Scripts
Cert                         Certificate \                                 
Env                          Environment                                   
Function                     Function                                      
HKCU                         Registry    HKEY_CURRENT_USER                 
HKLM                         Registry    HKEY_LOCAL_MACHINE                
Variable                     Variable                                      
WSMan                        WSMan  
#>

Get-ChildItem -Path 'env:\'
<#
Using these in code requires the $ in front of each named variable to get the content/values. In your scripts, never name your custom variables the same as any of the below. 

Name                            Value                                                                                                                 
----                            -----                                                                                                                 
ALLUSERSPROFILE                 C:\ProgramData                                                                                                        
APPDATA                         C:\Users\WDAGUtilityAccount\AppData\Roaming                                                                           
CLIENTNAME                      8fda9520-99a6-4                                                                                                       
CommonProgramFiles              C:\Program Files\Common Files                                                                                         
CommonProgramFiles(x86)         C:\Program Files (x86)\Common Files                                                                                   
CommonProgramW6432              C:\Program Files\Common Files                                                                                         
COMPUTERNAME                    0C092C31-6890-4
...  
#>

If you do want to use the names above, as custom variables for other values, then you should provide a unique prefix. Say, your initials, so as to not have conflicts/errors.