Find all the PDFs with at least three characters in their name I'd like to find the PDF files whose name (excluding the extension) is greater than three.

$ find ~  -iregex '.*/[^/]{3,}.pdf'


when test with

$ find ~ -regextype posix-extended -iregex '.*/[^/]{3,}.pdf'
find: -regextype: unknown primary or operator


How can I enable the {3,} variant?
How about find ~ -name '???*.pdf' ?