diff --git a/tools/define.bat b/tools/define.bat
index 42f1ee65f5..9a968e5bda 100755
--- a/tools/define.bat
+++ b/tools/define.bat
@@ -18,7 +18,7 @@ rem License for the specific language governing permissions and limitations
 rem under the License.
 
 rem Handle command line options
-rem [-h] <compiler-path> <def1> [-val <val1>] [<def2> [-val <val2>] [<def3> [-val <val3>] ...]]
+rem [-h] <compiler-path> <def1>[=val1] [<def2>[=val2] [<def3>[=val3] ...]]
 rem [-w] [-d] ignored for compatibility with define.sh
 
 set progname=%0
@@ -78,7 +78,7 @@ shift
 
 rem Handle the output depending on if there is a value for the variable or not
 
-if "%1"=="-val" goto :GetValue
+if not "%1"=="" goto :GetValue
 
 rem Handle the output using the selected format
 
@@ -110,7 +110,6 @@ goto :DefinitionLoop
 rem Get value following the variable name
 
 :GetValue
-shift
 set varvalue=%1
 shift
 
@@ -148,13 +147,13 @@ goto :End
 echo %progname% is a tool for flexible generation of command line pre-processor
 echo definitions arguments for a variety of diffent ccpaths in a variety of
 echo compilation environments"
-echo USAGE:%progname% [-h] ^<compiler-path^> [-val ^<^val1^>] [^<def2^> [-val ^<val2^>] [^<def3^> [-val ^<val3^>] ...]]
+echo USAGE:%progname% [-h] ^<compiler-path^> ^<def1^>[=^<val1^>] [^<def2^>[=^<val2^>] [^<def3^>[=^<val3^>] ...]]
 echo Where:"
 echo  ^<compiler-path^>
 echo    The full path to your ccpath
 echo  ^<def1^> ^<def2^> ^<def3^> ...
 echo    A list of pre-preprocesser variable names to be defined.
-echo  [-val ^<val1^>] [-val ^<val2^>] [-val ^<val3^>] ...
+echo  [=^<val1^>] [=^<val2^>] [=^<val3^>] ...
 echo    optional values to be assigned to each pre-processor variable.
 echo    If not supplied, the variable will be defined with no explicit value.
 echo  -h