I'm looking to make a directory have a certain umask (775) so every user who belongs to the appropriate group can have rw rights on this directory, keep the ownership, but also make it readable to other users of the group. Now my question is faily simple, how do I make such a directory? I've read about the -m flag for mkdir, but how exactly does it work (I've created a few test directories with it, but I don't seem to be able to keep the umask and every file created to keep that usmask). I know that if I was doing this from fstab while mounting a partition, this would be much easier (since you get to specify in fstab the options at mount time), but if I only want to apply settins like those to a single directory, is that even possible?