This hack emulates the HISTIGNORE functionality in bash. It only hides relevant commands in the readline UI, not the internal history file. To use, run it at startup via c.InteractiveShellApp.exec_files in your ipython_config.py

# our history_ignore predicate
history_ignore = lambda str: str.startswith("cd")

# hijack the readline.add_history method
get_ipython().readline.old_add_history = get_ipython().readline.add_history
def my_add_history(str):
    if not history_ignore(str):
        get_ipython().readline.old_add_history(str)

get_ipython().readline.add_history = my_add_history

#Force a readline history reload, forcing it to go through our hacked method
#WARNING: this relies on the internals of ipython refilling the history with "refill_readline_hist"
#This is up to date Oct 2011, but may change in the future.
get_ipython().readline.clear_history()
get_ipython().refill_readline_hist()