In ipython, I have the ipython_config.py
when I make changes in this file, how I can reload ipython ? (without restart ipython)
for example for change the prompt.
As far as I know, you can't - that file is read when you start IPython. You can change any configured value while IPython is running:
%config PromptManager.in_template = "\\#>>>"
That won't be stored in the config file, though.
%config TerminalInteractiveShell.editor = 'emacs'