bug#8729: RFE: chmod "-D" operate on dir's only

[Linda Walsh]

I know one can (and I usually do) construct a find command to do
this, but it's something I do so often, and it's a natural 'pair'
for what is often done with chmod.

If I want to make sure a dir tree is readable/accessable
by a group or other, I usually do:

 chmod -R g+r,o+r .
 find . -type d -print0|xargs -0 chmod g+x,o+x

What'd be a great addition to chmod is for it to have an option
for chmod to only work on dirs.  (is -D taken?)

So instead of the 2nd line above:

 chmod -DR g+x,o+x

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What'cha think?

Is that a useful and logical addition for chmod?