find /data -iname “myfile*.txt”
This will look in the /data partition for the files myfile1.txt, Myfile2.txt, etc.
The -iname makes the search case insensitive, which is what windows people are used to, whereas linux people can have two different files with the same name in the same directory! (different case)
Also note that Linux default sort on the Android makes the capital letter directories (folders) in front of the lowercase ones.
So Myfiles directory will not be next to myfiles2 directory!