When you don't enter a specific path for
find to look at, at least GNU find will default to search recursively from and including the current directory, i.e.
.. Verbatim from
If no paths are given, the current directory is used.
If you don't want to include the path argument itself in the results, add
-mindepth 1. Once again from
Do not apply any tests or actions at levels less than `levels` (a
non-negative integer). `-mindepth 1` means process all files except
the command line arguments.
~$ mkdir test
~$ cd test
~/test$ find -mindepth 0
~/test$ find -mindepth 1
With your specific command,
find will always return at least one record if the current directory itself is older than 20 minutes. Creating a new directory as you did will then not return anything, since it won't match the search criteria — at least not for 20 minutes after its creation.