for /f "tokens=* delims= " %%f in (myfile) do
This reads a file line-by-line, removing leading spaces (thanks, jeb).
set line=%%f
sets then the line variable to the line just read and
call :procesToken
calls a subroutine that does something with the line
:processToken
is the start of the subroutine mentioned above.
for /f "tokens=1* delims=/" %%a in ("%line%") do
will then split the line at /, but stopping tokenization after the first token.
echo Got one token: %%a
will output that first token and
set line=%%b
will set the line variable to the rest of the line.
if not "%line%" == "" goto :processToken
And if line isn't yet empty (i.e. all tokens processed), it returns to the start, continuing with the rest of the line.