@DEC[string] : Returns :

 

•-1 if string is empty

•otherwise the same value as @EVAL[string - 1]

 

If string is the name of an environment variable, its value is used whether or not it is preceded by a percent sign % without modifying the value of the variable. To actually decrement the value of the variable var use:

 

set var=%@dec[%var]

 

Example:

 

set start=5

set result=%@dec[start]

echo %result

4