How can I get the absolute path of a file deep within a directory?

Here's an example of directory level0 contents in a tree-like format. However, suppose it is huge and contains many files as I am omitting many of them here: $ tree level0 level0 └── level1 └── level2 └── sample.txt I tried using grep to check some file with grep, but this is the output I received: $ tree /tmp/level0 | grep sample └── sample.txt However, I expect the output to be the actual absolute path /tmp/level0/level1/level2/sample.txt. How can I get the file's absolute path deep within a directory using a command?