.. Define the common option diffcheck

**--diffcheck <key(s)>**

Specify what diff checks should be done in the **--diff** option above.

Comma separate multiple diff check key(s).  The available diff checks

are: **sw = switches**, **ca = channel adapters**, **router** = routers,

**port** = port connections, **lid** = lids, **nodedesc** = node

descriptions.  Note that **port**, **lid**, and **nodedesc** are

checked only for the node types that are specified (e.g. **sw**,

**ca**, **router**).  If **port** is specified alongside **lid**

or **nodedesc**, remote port lids and node descriptions will also be compared.