Import and trust a self-signed CA certificate from the Terminal

Question

Hello there,
i have a problem: I would like to import and trust a self-signed CA(root) certificate from the Terminal to the System.keychain.
My request is to create a installation script to install the Cisco AnyConnect VPN Client and the needed certificates.
For the import i have used the following command:
    sudo security import certificate.cer -k "/Library/Keychain/System.keychain" -A
    The Option "-A" says:
Allow any application to access the imported key without warning (insecure, not recommended!) <- From the Mac Developer Library
The command reportet: 1 certificate is importet ... but ... the certificate is not trusted.
What do i need to do to set this certificate as trustworthy at the terminal?
Thanks for your help and best regards
Benjamin
P.S. The command: sudo security add-trusted-cert -d -r trustRoot -k “/Library/Keychains/System.keychain” “/private/tmp/certs/certname.cer” doen't run, i get an error message. Found on http://derflounder.wordpress.com/2011/03/13/adding-new-trusted-root-certificates -to-system-keychain/

Answer 1

Hello Linc Davis,
thanks for your answer and sorry for my mistake, because i had already changed the last argument but for this discussion i had only copy this example.
But your answer show me the right way, big thanks.
I had entred the following command (see the last argument):
     sudo security add-trusted-cert -d -r trustRoot -k "/Library/Keychains/System.keychain" "~/Downloads/mycert.cer"
... and i get the following message:
    ***Error reading file ~/Downloads/mycert.cer
     Error reading file ~/Downloads/mycert.cer
Today i changed the last argument to:
     /Users/User/Downloads/mycert.cer
and its run.
Many thanks!
Benjamin