Alternatively, if you just want to check if the string is in the file, used the DOS "FIND" command.

For example:
code:
FIND /I "string" myfile.txt

Will search myfile.txt for "string".

The exit code will be "0" if the string is present, and "1" if it is not.

In KiXtart you can "Shell" the command and check @ERROR or %ERRORLEVEL%