change all file name in once

(1) 用記事本在桌面建立 REN1.BAS，內容如下：
1000 '程序目的：把 C:\CHK-JPG\*.CHK 更名為 *.JPG
1010 CLS:CLEAR:KEY OFF
1020 DDDN$="REN1"
1030 KEY 8,"SYSTEM"+CHR$(13)
1040 KEY 9,"RENUM 1000"+CHR$(13)
1050 KEY 10,"SAVE"+CHR$(34)+DDDN$+CHR$(34)+",A"+CHR$(13)
1060 'END
1070 OPEN "O",#2,"REN2.BAT"
1080 OPEN "I",#1,"DIR.TXT"
1090 IF EOF(1) THEN SYSTEM
1100 LINE INPUT #1,A$
1110 A$=MID$(A$,1,LEN(A$)-4)
1120 PRINT #2,"REN "+CHR$(34)+"C:\CHK-JPG\"+A$+".CHK"+CHR$(34)+" "+CHR$(34)+A$+".JPG"+CHR$(34)
1130 GOTO 1090
(2) 用記事本在桌面建立 REN1.BAT，內容如下：
:REN1.BAT
@ECHO OFF
CLS
DIR C:\CHK-JPG /B >DIR.TXT
GWBASIC REN1.BAS
EXIT
(3) 把 GWBASIC.EXE 放到桌面
(4) 把 *.CHK 放入「C:\CHK-JPG」資料夾裡面
(5) 左擊 REN1.BAT
(6) 左擊 REN2.BAT