Operating with Cold Keys

One of the primary things to keep in mind about cold keys is that they are often kept on cold nodes which are not connected to a main blockchain and are offline.
The primary use of cold keys is to generate a operational certificate along with the verification key and KES period.
This will show the code needed to generate an operational certificate or node.cert:
cardano-cli shelley node issue-op-cert \
--kes-verification-key-file kes.vkey \
--cold-signing-key-file cold.skey \
--operational-certificate-issue-counter cold.counter \
--kes-period 65 \
--out-file node.cert