pkg(1) list add feature for listing categories

[Lubos Kocman]

Hi,

I was playing with pkg(5) for a while, and find out that there is no way to
list fmris trough categories in the pkg(1) command.

I tried to create a simple implementation and add an option -c (stands for
category), some variables category_specified and category_name. Add one if
statement to the for cycle in list_inventory(). But I do beliveve that there
is much more efficient way how to solve this.

If there is such a way to do it without modifing source please let me know.
The other way is to use awk :-)