Enter PEM pass phrase just once

As suggested by Mikael, you can remove the pass phrase from the Key. Do note that this presents a serious security risk.

To remove the pass phrase from the Key, perform the following steps. Say you have a file called foo.pem with the following contents:

-----BEGIN ENCRYPTED PRIVATE KEY-----
...
-----END ENCRYPTED PRIVATE KEY-----
-----BEGIN CERTIFICATE-----
...
-----END CERTIFICATE-----

Execute the following command:

openssl rsa -in foo.pem -out foo_unencrypted.pem

You will be prompted for the pass phrase, and in return receive a file foo_unencrypted.pem that contains the following:

-----BEGIN RSA PRIVATE KEY-----
...
-----END RSA PRIVATE KEY-----

This file is missing the BEGIN CERTIFICATE ---- END CERTIFICATE section from above, so copy-paste it from foo.pem to the end of foo_unencrypted.pem:

-----BEGIN RSA PRIVATE KEY-----
...
-----END RSA PRIVATE KEY-----
-----BEGIN CERTIFICATE-----
...
-----END CERTIFICATE-----

If you use the file foo_unencrypted.pem, you will now no longer be prompted to "Enter PEM pass phrase".