The following command:
find . -name \"file2015-0*\" -exec mv {} .. \\;
Affects about 1500 results. One by one they move a previous level.>
You can do this:
find . -name "file2015-0*" | head -400 | xargs -I filename mv filename ..
If you want to simulate what it does use echo:
echo
find . -name "file2015-0*" | head -400 | xargs -I filename echo mv filename ..