-M is 40% faster than (stat)[9], no wonder, it does look only at modification time and doesn't build a list.
It doesn't build a list but it stores all the values from stat. From the -X man page:
If any of the file tests (or either the "stat" or "lstat" operators) are given the special filehandle consisting of a solitary underline, then the stat structure of the previous file test (or stat operator) is used, saving a system call.
So when you use -M _ or -f _ you are retrieving the stored values from the previous stat or file test.

In reply to Re^2: grab newest file by jwkrahn
in thread grab newest file by hasimir44

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