-m Mode Sets the permission bits for the newly-created directories to the value specified by the Mode variable. The Mode variable takes the same values as the Mode parameter for the chmod command, either in symbolic or numeric form.
When you specify the -m flag using symbolic format, the op characters + (plus) and - (minus) are interpreted relative to the assumed permission setting a=rwx. The + adds permissions to the default mode, and the - deletes permissions from the default mode. Refer to the chmodcommand for a complete description of permission bits and formats.