Concatenate.bat how-to contatenate specific file types in win cmd

ECHO EMPTY THE FILE
ECHO REMOVE THE OUTPUT FILE ALREADY ...
ECHO. >all.txt

ECHO FOR EACH LOG FILE IN THE CURRENT DIRECTORY DO CONTCATENATE IT
ECHO IN THE ALL.TXT FILE
for /f %%i in ('dir *.cmd *.sql /s /b /a-d') do echo . >>all.txt&ECHO START ===== %%i>>all.txt&type %%i>>all.txt&ECHO. >>all.txt&echo END ================== %%i>>all.txt&ECHO. >>all.txt
PAUSE
ECHO OPEN THE ALL.TXT FILE
all.txt