security

Administer Keychains, keys, certificates and the Security framework. More information: https://ss64.com/osx/security.html.

List the available keychains:

security list-keychains

Delete a specific keychain:

security delete-keychain {{path}}

Create a keychain:

security create-keychain -p {{password}} {{keychain.name}}

Set a certificate to use with a website or [s]ervice by its [c]ommon name (fails if several certificates with the same common name exist):

security set-identity-preference -s {{URL|hostname|service}} -c "{{common_name}}" {{path/to/file.keychain}}

Add a certificate from file to a [k]eychain (if -k isn't specified, the default keychain is used):

security add-certificates -k {{keychain.name}} {{path/to/file.pem}}