CrLf

@echo off
set /a min=30*1024*1024*1024
set "min=000000000000000000%min%"
set "min=%min:~-20%"
for %%a in (*.dbf) do (
   set "file=%%a"
   set "size=000000000000000000%%~za"
   setlocal enabledelayedexpansion
   if !size:~-20! gtr !min! echo !file!
   endlocal
)
pauseCOPY

CrLf

@echo off
set /a min=30*1024*1024*1024
set "min=000000000000000000%min%"
set "min=%min:~-20%"
(echo %min%
for %%a in (*.dbf) do (
   set "file=%%a"
   set "size=000000000000000000%%~za"
   setlocal enabledelayedexpansion
   echo !size:~-20!:!file!
   endlocal
))>tmp.txt
for /f "tokens=1* delims=:" %%a in ('sort tmp.txt') do (
   if defined flag echo;%%b
   if %%a==%min% set flag=yes
)
pauseCOPY