How to write a search pattern to include a space in findstr?

Question

I want to search all files in a certain directory for occurrences of statements such as

  Load frmXYZ

I am on Windows 7, using the f

Answer 1

This piece of code will only allow letters, numbers, underscore and white space in keyword:

set /p keyword="Enter keyword: " || Set keyword=

set keyword_replaced=%keyword: =_%

echo %keyword_replaced%| findstr /r "[^0-9a-zA-Z_]" > nul
if errorlevel 1 goto noexit
echo special characters in keyword not allowed (except space and _), TERMINATING
timeout 4
exit /b 0
:noexit