Cookbook:-Dynamic-prompt.mediawiki

This assumes IPython 0.12

I used IPython to create a custom shell for a project at work. I wanted the prompt to show some status information about the state of the system it was controlling.

ED: I've changed these examples to use the config system. You can do the same things with an embedded instance of IPython .

First, we change the default ipython_config.py file, adding these lines:

 # _foobar will be the part of the prompt we control
 c.PromptManager.in_template = "[{_foobar}]\n[\#]>>> "
 c.PromptManager.in2_template = ".\D.>>> "
 c.PromptManager.out_template = "[\#]<<< "

Next, we prepare our variable, ensuring it has a `__str__()` method for the prompt formatter to call:

This code goes in a startup file. Create a file such as `foobar_prompt.py` in `profile_default/startup/`

```python

 del FoobarPrompt

```

Expected output: ``` $ ipython

[foo] [1]>>> _foobar.var = "blah"

[UNKNOWN] [2]>>> _foobar.var = "BAR"

[BAR] [3]>>> _foobar [3]<<< <.FoobarPrompt at 0x25c2f90>

[BAR] [4]>>> ```

You can also automatically set the state from the `pre_run_code_hook` (gets run every time code is executed) or the `pre_prompt_hook` (gets run just before the prompt is printed).

```python

 get_ipython().set_hook("pre_prompt_hook", update_prompt)

```

Finally, there are a number of built in prompt variables:

Built in prompt templates

Short	Long	Notes
%n, \#	{color.number}{count}{color.prompt}	history counter with bolding
\N	{count}	history counter without bolding
\D	{dots}	series of dots the same width as the history counter
\T	{time}	current time
\w	{cwd}	current working directory
\W	{cwd_last}	basename of CWD
\Xn	{cwd_x[n]}	Show the last n terms of the CWD. n=0 means show all.
\Yn	{cwd_y[n]}	Like \Xn, but show '~' for $HOME
\h	N/A	hostname, up to the first '.'
\H	N/A	full hostname
\u	N/A	username (from the $USER environment variable)
\v	N/A	IPython version
\$	N/A	root symbol ("$" for normal user or "#" for root)
\\	N/A	escaped '\'
\n	N/A	newline
\r	N/A	carriage return

On terminals supporting ANSI color switching, you can also use the following color variables: ```

1. attributes of IPython.utils.coloransi.InputTermColors

{color.Black} {color.Green} {color.BlinkBlack} {color.LightBlue} {color.BlinkBlue} {color.LightCyan} {color.BlinkCyan} {color.LightGray} {color.BlinkGreen} {color.LightGreen} {color.BlinkLightGray} {color.LightPurple} {color.BlinkPurple} {color.LightRed} {color.BlinkRed} {color.Purple} {color.BlinkYellow} {color.Red} {color.Blue} {color.White} {color.Brown} {color.Yellow} {color.Cyan} {color.Normal} (resets to terminal default) {color.DarkGray} (try {color.normal} if above doesn't work) ``` So...

 c.PromptManager.in_template = "{color.LightGreen} \T {color.Yellow} \Y2 "

will produce a prompt with green time and yellow CWD.