The following useful information is primarily taken from the Windows PowerShell Language Quick Reference (QuadFold.rtf) documentation.

Automatic Variables

PowerShell includes the following in-built variables:

Variable Declaration

Variables and other data elements may be instantiated in different scopes:

• Variables in the global scope are visible in all scopes.
• Variables in the script scope are visible to all scopes within that script file.
• Variables in the local scope are visible only in the current scope and its children.
• Private scope variables are visible only to that current scope.

A scope is created in the body of a shell function.

Format:

1$[scope:]name or ${anyname} or ${any path}

Examples:

1$a = 1
2$global:a = 1    # Visible everywhere
3$local:a = 1    # defined in this scope and visible to children
4$private:a=1    # same as local but invisible to child scopes
5$script:a=1    # visible to everything in this script
6$env:path = "d:\windows"
7${C:\TEMP\testfile.txt}="This writes to a file"
8Get-Variable -scope 1 a    #Gets value from the parent scope
9Get-Variable -scope 2 a    # grandparent

Type Declaration

Variables also can be declared as specific data type by prefixing the variable declaration with the data type.

A variable’s type also can be declared as a .NET Framework class by using the full class name. For example:

1[System.Int32] $amount = 1234