how to find a file in linux terminal

find /path/to/folder/ -iname *file_name_portion*

find /path/to/folder/ -iname *file_name_portion*

#Example
find / -iname *test*

#Output

/downloads/test_2.txt
/downloads/test_1.csv
/home/ubuntu/first_test.txt

// 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\*