This will recursively search all the files, with a certain filename pattern (in this case *.h) in a certain directory, that contains a certain text pattern in its contents (in this case ‘DeviceDriver’).

find . -name '*.h' -print0 
| xargs -0 grep -n -e DeviceDriver

[I could never remember this so I’m putting it here.]
These are the fields of a crontab file:

a b c d e /full/path/to/script

where

a = minute (0-59),
b = hour (0-23),
c = day of the month (1-31),
d = month of the year (1-12),
e = day of the week (0-6 with 0=Sunday).

* = every min, hour, day, etc.
*/10 = every 10 min, hour, day, etc.