IF [NOT] ERRORLEVEL number          command
IF [NOT] string1==string2           command
IF [NOT] EXIST filename             command
IF CMDEXTVERSION number             command
IF DEFINED variable                 command
IF [/I] string1 compare-op string2  command
   where compare-op is:
   EQU - equal
   NEQ - not equal
   LSS - less than
   LEQ - less than or equal
   GTR - greater than
   GEQ - greater than or equal
   /I    case insensitive string compares