ÃOMMAND:    IF
 
ÓYNTAX:     IF EXIST PATTERN COMMAND
            IF STRING1 = STRING2 COMMAND
            IF ERRORLEVEL N COMMAND
 
ÓEE ÁLSO:   ÂÁÔÃÈ, ÂÅÇÉÎ, ÌÏÏÐ, ÇÏÔÏ, ÇÅÔËÅÙ, ;
 
    IF IS USED TO CONTROL THE ACTION TAKEN INSIDE BATCH FILES.
 
    ÃOMMAND CAN BE A ÂÁÓÉÃ COMMAND OR A ÃÓ-ÄÏÓ COMMAND.
 
    ÏNLY A FEW ÃÓ-ÄÏÓ COMMANDS RETURN ERRORLEVELS THAT MAKE ANY SENSE.
ÕSUALLY THEY DON'T. ÉN GENERAL, THOUGH, AN ERRORLEVEL OF ZERO MEANS
THE COMMAND DID WHAT YOU EXPECTED IT TO DO AND ANY OTHER VALUE MEANS
THAT IT FAILED FOR ONE REASON OR ANOTHER.
 
        IF EXIST PATTERN COMMAND
 
    ÔHIS EXECUTES COMMAND ONLY IF THE FIRST FILE MATCHING PATTERN EXISTS.
 
        IF STRING1 = STRING2 COMMAND
 
    ÔHIS EXECUTES COMMAND ONLY IF THE TWO STRINGS ARE THE SAME.
 
        IF ERRORLEVEL N COMMAND
 
    ÔHIS EXECUTES COMMAND ONLY IF THE LAST COMMAND RETURNED AN ERRORLEVEL OF N.
 
 
    ÆOR EXAMPLE, HERE IS A BATCH FILE TO IMPROVE UPON THE DEL COMMAND.
ÌETS SAY WE CALL THIS "ERASE"
 
        IF "%1" = " " GOTO USAGE
        IF "%2" = "IFON" GOTO DELIF
        DEL %1 %2 %3 %4 %5 %6 %7 %8 %9
        GOTO DONE
        :DELIF
        IF "%3" = " " GOTO USAGE
        IF EXIST %3%1 DEL %1
        GOTO DONE
        :USAGE
        ECHO USAGE %0 FILENAME [IFON D:]
        :DONE
        ;
 
    ÓO THAT INVOKING IT WITH
 
        ERASE NAME
 
    ×OULD BE THE SAME AS
 
        DEL NAME
 
    ÂUT INVOKING IT WITH
 
        ERASE NAME IFON B:
 
    ×OULD ONLY DELETE THE FILE IF A FILE WITH THE SAME NAME EXISTED ON DRIVE B:
 
 
    ÏR HERE IS A BATCH FILE TO ASSEMBLE AND REINSTALL SOME PROGRAM. ÓUPPOSE WE
CALL IT "ASSM", THEN INVOKE IT WITH ->  ASSM NAME
 
 
        ASM %1.ASM %1
        IF NOT ERRORLEVEL 0 GOTO ERROR
        REMOVE %1
        INSTALL %1
        GOTO DONE
        :ERROR
        ECHO ÁSSEMBLY ERROR.
        :DONE
        ;