DelayedExpansion
HKLM\SOFTWARE\Microsoft\Command Processor
Data type |
Range |
Default value |
|---|---|---|
REG_DWORD |
0 | 1 |
0 |
Description
Determines whether the command processor supports delayed expansion of environment variables. If the value of this entry is 1, the command processor interprets an exclamation point, !, as an environment variable expands only when used.
By default, the command processor expands variables when it reads a line of text. But you can direct the command processor to expand a variable only when it is used. As a result, you can include variables in compound conditional statements and prevent them from being set before they are tested.
Value |
Meaning |
|---|---|
0 |
Delayed expansion is not supported. The command processor expands environment variables when it reads them. It does not support exclamation points as delayed variables. |
1 |
Delayed expansion is supported. The system expands environment variables surrounded by exclamation points, such as !VAR!, only when they are used. |
Change method
To change the value of this entry, start the Command Processor (Cmd.exe) and type cmd /v:on.
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Note
The DelayedExpansion entry can appear in HKEY_LOCAL_MACHINE and HKEY_CURRENT_USER. If both appear in the registry, the value of the entry in HKEY_CURRENT_USER takes precedence over the value in HKEY_LOCAL_MACHINE.
Windows 2000 does not add this entry to the registry. You can add it by editing the registry or by using a program that edits the registry. Even when this entry appears in the registry, the setting of the command line switch, /V, takes precedence over this value.
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Tip
For more details, start the Command Processor (Cmd.exe), type either help set or cmd /?, and read the entry on the /V command.
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