Linux to find a file containing a string under a directory

Sometimes to find a program written before, but a long time forgetful, only remember that the program fragment contains a text.

So how do you find a file that contains a piece of text under Linux?

The powerful find command can help you accomplish impossible tasks.

For example, I only remember that my program contains a unique string "111cn.net", so:

Find out if any of the files in the directory contain a string

Find. | Xargs Grep-ri "111cn.net"

Find out if any of the files in the directory contain a string, and only the file name is printed

Find. | Xargs Grep-ri "111cn.net"-l

Is it very simple?