The following example shows how to test for the existence of an environment
IF "%VARIABLE%" == "" GOTO MODULE
This example checks for the existence of the environment variable
"VARIABLE." If VARIABLE does not exist, the statement is true and control
of the batch file jumps to the MODULE section. If the statement is not
true, that is, the VARIABLE variable does exist, program control skips to
the next line of the batch file and continues.
NOTE: The quotation marks are necessary only when a variable is used in a
logical IF statement.
The following example illustrates the use of the PATH environment variable
within a batch file:
IF "%PATH%" == "" GOTO NOPATH
@ECHO The PATH environment variable was detected.
@ECHO The PATH environment variable was NOT detected.
This example tests for the existence of the PATH variable. If it exists,
control passes to the YESPATH section; otherwise, control is passed to the
If a path is detected and control is passed to the YESPATH section, C:\DOS
is added to the existing path by using the %PATH% variable.