Specific config details — IPython 2.3.1 documentation

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# Specific config details

## Prompts

In the terminal, the format of the input and output prompts can be customised. This does not currently affect other frontends.

The following codes in the prompt string will be substituted into the prompt string:

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 |  | hostname, up to the first ‘.’
\H |  | full hostname
\u |  | username (from the $USER environment variable)
\v |  | IPython version
\$ |  | root symbol (“$” for normal user or “#” for root)
`\\` |  | escaped ‘\’
\n |  | newline
\r |  | carriage return
n/a | {color.<Name>} | set terminal colour - see below for list of names

Available colour names are: Black, BlinkBlack, BlinkBlue, BlinkCyan, BlinkGreen, BlinkLightGray, BlinkPurple, BlinkRed, BlinkYellow, Blue, Brown, Cyan, DarkGray, Green, LightBlue, LightCyan, LightGray, LightGreen, LightPurple, LightRed, Purple, Red, White, Yellow. The selected colour scheme also defines the names prompt and number. Finally, the name normal resets the terminal to its default colour.

So, this config:

    c.PromptManager.in_template = "{color.LightGreen}{time}{color.Yellow} \u{color.normal}>>>"

will produce input prompts with the time in light green, your username in yellow, and a `>>>` prompt in the default terminal colour.

## Terminal Colors

The default IPython configuration has most bells and whistles turned on (they’re pretty safe). But there’s one that may cause problems on some systems: the use of color on screen for displaying information. This is very useful, since IPython can show prompts and exception tracebacks with various colors, display syntax-highlighted source code, and in general make it easier to visually parse information.

The following terminals seem to handle the color sequences fine:

> - Linux main text console, KDE Konsole, Gnome Terminal, E-term, rxvt, xterm.
> - CDE terminal (tested under Solaris). This one boldfaces light colors.
> - (X)Emacs buffers. See the (X)Emacs section for more details on using IPython with (X)Emacs.
> - A Windows (XP/2k) command prompt with pyreadline.
> - A Windows (XP/2k) CygWin shell. Although some users have reported problems; it is not clear whether there is an issue for everyone or only under specific configurations. If you have full color support under cygwin, please post to the IPython mailing list so this issue can be resolved for all users.

These have shown problems:

> - Windows command prompt in WinXP/2k logged into a Linux machine via telnet or ssh.
> - Windows native command prompt in WinXP/2k, without Gary Bishop’s extensions. Once Gary’s readline library is installed, the normal WinXP/2k command prompt works perfectly.

Currently the following color schemes are available:

> - NoColor: uses no color escapes at all (all escapes are empty ‘’ ‘’ strings). This ‘scheme’ is thus fully safe to use in any terminal.
> - Linux: works well in Linux console type environments: dark background with light fonts. It uses bright colors for information, so it is difficult to read if you have a light colored background.
> - LightBG: the basic colors are similar to those in the Linux scheme but darker. It is easy to read in terminals with light backgrounds.

IPython uses colors for two main groups of things: prompts and tracebacks which are directly printed to the terminal, and the object introspection system which passes large sets of data through a pager.

If you are seeing garbage sequences in your terminal and no colour, you may need to disable colours: run `%colors NoColor` inside IPython, or add this to a config file:

    c.InteractiveShell.colors = 'NoColor'

### Colors in the pager

On some systems, the default pager has problems with ANSI colour codes. To configure your default pager to allow these:

1. Set the environment PAGER variable to `less`.
2. Set the environment LESS variable to `-r` (plus any other options you always want to pass to less by default). This tells less to properly interpret control sequences, which is how color information is given to your terminal.

## Editor configuration

IPython can integrate with text editors in a number of different ways:

- Editors (such as (X)Emacs, vim and TextMate) can send code to IPython for execution.
- IPython’s `%edit` magic command can open an editor of choice to edit a code block.

The %edit command (and its alias %ed) will invoke the editor set in your environment as `EDITOR`. If this variable is not set, it will default to vi under Linux/Unix and to notepad under Windows. You may want to set this variable properly and to a lightweight editor which doesn’t take too long to start (that is, something other than a new instance of Emacs). This way you can edit multi-line code quickly and with the power of a real editor right inside IPython.

You can also control the editor by setting `TerminalInteractiveShell.editor` in `ipython_config.py`.

### Vim

Paul Ivanov’s vim-ipython provides powerful IPython integration for vim.

### (X)Emacs

If you are a dedicated Emacs user, and want to use Emacs when IPython’s `%edit` magic command is called you should set up the Emacs server so that new requests are handled by the original process. This means that almost no time is spent in handling the request (assuming an Emacs process is already running). For this to work, you need to set your EDITOR environment variable to ‘emacsclient’. The code below, supplied by Francois Pinard, can then be used in your `.emacs` file to enable the server:

    (defvar server-buffer-clients)
    (when (and (fboundp 'server-start) (string-equal (getenv "TERM") 'xterm))
      (server-start)
      (defun fp-kill-server-with-buffer-routine ()
        (and server-buffer-clients (server-done)))
      (add-hook 'kill-buffer-hook 'fp-kill-server-with-buffer-routine))

Thanks to the work of Alexander Schmolck and Prabhu Ramachandran, currently (X)Emacs and IPython get along very well in other ways.

Note

You will need to use a recent enough version of `python-mode.el`, along with the file `ipython.el`. You can check that the version you have of `python-mode.el` is new enough by either looking at the revision number in the file itself, or asking for it in (X)Emacs via `M-x py-version`. Versions 4.68 and newer contain the necessary fixes for proper IPython support.

The file `ipython.el` is included with the IPython distribution, in the directory `docs/emacs`. Once you put these files in your Emacs path, all you need in your `.emacs` file is:

    (require 'ipython)

This should give you full support for executing code snippets via IPython, opening IPython as your Python shell via `C-c !`, etc.

You can customize the arguments passed to the IPython instance at startup by setting the `py-python-command-args` variable. For example, to start always with `matplotlib` integration and hardcoded light-background colors, you can use:

    (setq py-python-command-args '("--matplotlib" "--colors" "LightBG"))

If you happen to get garbage instead of colored prompts as described in the previous section, you may need to set also in your `.emacs` file:

    (setq ansi-color-for-comint-mode t)

Notes on emacs support:

- There is one caveat you should be aware of: you must start the IPython shell before attempting to execute any code regions via `C-c |`. Simply type `C-c !` to start IPython before passing any code regions to the interpreter, and you shouldn’t experience any problems. This is due to a bug in Python itself, which has been fixed for Python 2.3, but exists as of Python 2.2.2 (reported as SF bug [ 737947 ]).
- The (X)Emacs support is maintained by Alexander Schmolck, so all comments/requests should be directed to him through the IPython mailing lists.
- This code is still somewhat experimental so it’s a bit rough around the edges (although in practice, it works quite well).
- Be aware that if you customized `py-python-command` previously, this value will override what `ipython.el` does (because loading the customization variables comes later).

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