Variables that are created and declared by Windows PowerShell
Shell variables are a set of variables that are created and declared by Windows PowerShell and appear by default in every Windows PowerShell session. The variables are maintained throughout the session and are available to all commands, scripts, and applications that run in that session.
Windows PowerShell supports two types of shell variables:
· Automatic variables: Store the state of Windows PowerShell. These variables are maintained by the system and changed dynamically. Users cannot (and should not) change the value of these variables. For example, the $PID variable stores the process ID of the current PowerShell.exe process.
· Preference variables: Store user preferences for Windows PowerShell. These variables are created by Windows PowerShell and populated with default values. Users can change the values of these variables. For example, MaximumHistoryCount determines the maximum number of entries in the session history.
You can use shell variables as you would any other type of variable. For example, you can use the $pshome shell variable, which stores the path to the Windows PowerShell installation directory, as the value of the Path variable in a Get-Childitem command. For example:
For information about PowerShell system state, type:
For information about automatic variables, type: