I email my scripts frequently. To get through email filters I change them to a text file. This script will convert a file from file.ext to file_ext.txt. You can use the file name as an argument or drop and drag. The routines came from http://www.robvanderwoude.com (updated 7/18)
@ECHO OFF
SetLocal
rem handle multiple drop and drag
:Loop
IF %1==”” GOTO Exit
rem strip leading . from ext
set EXT=%~x1
set EXT=%EXT:.=%
ren %1 “%~n1_%EXT%.txt”
SHIFT
goto Loop
:Exit
endlocal
pause