mkdir
[options] directoriesCreate one or more directories. You must have write permission in the parent directory in order to create a directory. See also rmdir.
-m
modeSet the access mode for new directories.
-p
Create intervening parent directories if they don't exist.
Create a read/execute-only directory named personal:
mkdir -m 555 personal
The following sequence:
mkdir work; cd work
mkdir junk; cd junk
mkdir questions; cd ../..
could be accomplished by typing this:
mkdir -p work/junk/questions