Getting substrings in a batchfile requires you to use the %…:~…% syntax as explained by Rob van der Woude.
Note this only works on batch file variables, so not on batch/function arguments (%1, %2, …)and for-loop indexes (%%f, etc).
This code gets the leftmost three characters of var:
set var=%var:~3%
echo %var%
–jeroen
via Remove the first 3 characters in var in batch file? – Stack Overflow.
The Wiert Corner - irregular stream of stuff 