how to search in directory files in ubuntu

> grep "the_search" ~/.bash_history

--Don't forget the -i flag if you need case insensitive search.// Using backslash and asterisk (\*) at the end will search for all files that start with your search term (in this case "readme"). So you would also be able to find "readme2" etc. 
find . -name readme\*# this will search all subdirectories for your text (no case sensitivity)
# it also prints the line number of the text in file
grep -inR "your text" .