Code:

DECLARE SUB aMain ()DECLARE FUNCTION StatusFile% (f AS STRING)DIM SHARED MyErr AS INTEGERCALL aMainSYSTEMGetMyErr: MyErr = ERR: RESUME NEXT    REM NOTE....SUB aMainCLS : LOCATE 2, 20: PRINT "Testing function StatusFile": PRINTPRINT "Enter file names to be tested. Just press Enter when finished."DO  PRINT  LINE INPUT "fname: "; f$  IF f$ = "" THEN EXIT DO  SELECT CASE StatusFile(f$)  CASE 0: PRINT "Bad File Name"  CASE 1: PRINT "Exists"  CASE 2: PRINT "Does not exist"  END SELECTLOOPSYSTEMEND SUBFUNCTION StatusFile% (f AS STRING)IF LEN(f) = 0 THEN EXIT FUNCTION' Ensure no spaces anywhereIF INSTR(t$, " ") > 0 THEN EXIT FUNCTION' Separate file name from path, if anyDIM y AS INTEGERFOR y = LEN(f) TO 1 STEP -1  SELECT CASE MID$(f, y, 1)  CASE "", "/", ":": EXIT FOR  CASE " ": EXIT FUNCTION  END SELECTNEXT yIF y = 1 THEN t$ = f ELSE t$ = RIGHT$(f, LEN(f) - y)' Test for prefix(8 max).suffix(3 max)FOR y = LEN(t$) TO 1 STEP -1  IF MID$(t$, y, 1) = "." THEN    IF LEN(t$) - y > 3 THEN EXIT FUNCTION' suffix>3    IF y = 1 THEN EXIT FUNCTION ' name was just "."    t$ = LEFT$(t$, y - 1): EXIT FOR  END IFNEXT yIF LEN(t$) > 8 THEN EXIT FUNCTION' OK, now test whole thing for reaMaining errorsMyErr = 0: ON ERROR GOTO GetMyErr   REM NOTE....OPEN f FOR INPUT AS #1: CLOSEON ERROR GOTO 0                          REM NOTE...IF MyErr = 0 THEN StatusFile% = 1   REM NOTE....IF MyErr = 53 THEN StatusFile% = 2  REM NOTE....END FUNCTION

Code:

c$ = command$     'get the command-line, except for the .EXE name.s = instr(c$," ")     'find location of space delimiter between filenames.if s = 0 then print "Invalid or missing filenames" : systemfilold$ = left$(c$,s-1)     'Get leftmost filename.filold$ = ltrim$(rtrim$(filold$))     'Get rid of any leading or trailing spaces.filnew$ = mid$(c$,s+1)     'Get leftmost filename.filnew$ = ltrim$(rtrim$(filnew$))