The way bash invoked means that (unless you changed something) it will emulate a login-shell and thus source the global profile followed by the first of .bash_profile, .bash_login or .profile in your homedir.
The duplicate line command consists of 'echo' and some bash variable substitutions.
I had an issue once where I had some auto-complete things setup for bash that took a long time to load, slowed down all my commands. Allan helped me set it up so it only activated when a interactive shell was used. I'd tell you how he did it but it was on my old computer, not sure I still have the file.