I'm trying to do a number comparison in a ms-dos batch file. I have the following code

set /a lastmonth_=%monthnr_%-1
echo %lastmonth_%
if %lastmonth_% < 10 set %lastmonth_% = 0%lastmonth_%
echo %lastmonth_%

the "< 10" isn't working - says something about < is unexpected.

How do you do number comparisons in MS DOS batch files?

Thanks.