Using the terminal, till now I have not been able to figure out how to find a file(relative path from current directory) which may lie several layers below in the directory structure.
The best I figured out is :
ls -R | grep file_name
The answer is in ring bearer comment. I will just mark it here so that other people having the same issue can easily take the answer home.
find command as
find . -name file_name
or if you don't know the filename but just a part of the file name then you can use this
find . -name *file_name_part*