ipython - An Enhanced Interactive Python
ipython [options] files...
An interactive Python shell with automatic history (input and output),
dynamic object introspection, easier configuration, command completion,
access to the system shell, integration with numerical and scientific
computing tools, and more.
SPECIAL THREADING OPTIONS
The following special options are ONLY valid at the beginning of the
command line, and not later. This is because they control the
initialization of ipython itself, before the normal option-handling
mechanism is active.
-gthread, -qthread, -q4thread, -wthread, -pylab
Only ONE of these can be given, and it can only be given as the
first option passed to IPython (it will have no effect in any
other position). They provide threading support for the GTK,
QT3, QT4 and WXWidgets toolkits, for the matplotlib library and
With any of the first four options, IPython starts running a
separate thread for the graphical toolkit’s operation, so that
you can open and control graphical elements from within an
IPython command line, without blocking. All four provide
essentially the same functionality, respectively for GTK, QT3,
QT4 and WXWidgets (via their Python interfaces).
Note that with -wthread, you can additionally use the -wxversion
option to request a specific version of wx to be used. This
requires that you have the wxversion Python module installed,
which is part of recent wxPython distributions.
If -pylab is given, IPython loads special support for the
matplotlib library (http://matplotlib.sourceforge.net), allowing
interactive usage of any of its backends as defined in the
user’s .matplotlibrc file. It automatically activates GTK, QT
or WX threading for IPyhton if the choice of matplotlib backend
requires it. It also modifies the %run command to correctly
execute (without blocking) any matplotlib-based script which
calls show() at the end.
-tk The -g/q/q4/wthread options, and -pylab (if matplotlib is
configured to use GTK, QT or WX), will normally block Tk
graphical interfaces. This means that when GTK, QT or WX
threading is active, any attempt to open a Tk GUI will result in
a dead window, and possibly cause the Python interpreter to
crash. An extra option, -tk, is available to address this
issue. It can ONLY be given as a SECOND option after any of the
above (-gthread, -qthread, -wthread or -pylab).
If -tk is given, IPython will try to coordinate Tk threading
with GTK, QT or WX. This is however potentially unreliable, and
you will have to test on your platform and Python configuration
to determine whether it works for you. Debian users have
reported success, apparently due to the fact that Debian builds
all of Tcl, Tk, Tkinter and Python with pthreads support. Under
other Linux environments (such as Fedora Core 2), this option
has caused random crashes and lockups of the Python interpreter.
Under other operating systems (Mac OSX and Windows), you’ll need
to try it to find out, since currently no user reports are
There is unfortunately no way for IPython to determine at
runtime whether -tk will work reliably or not, so you will need
to do some experiments before relying on it for regular work.
After the above threading options have been given, regular options can
follow in any order. All options can be abbreviated to their shortest
non-ambiguous form and are case-sensitive. One or two dashes can be
used. Some options have an alternate short form, indicated after a |.
Most options can also be set from your ipythonrc configuration file.
See the provided examples for assistance. Options given on the
commandline override the values set in the ipythonrc file.
All options with a [no] prepended can be specified in negated form
(-nooption instead of -option) to turn the feature off.
Show summary of options.
Make IPython automatically call any callable object even if you
didn’t type explicit parentheses. For example, ’str 43’ becomes
str(43) automatically. The value can be ’0’ to disable the
feature, ’1’ for ’smart’ autocall, where it is not applied if
there are no more arguments on the line, and ’2’ for ’full’
autocall, where all callable objects are automatically called
(even if no arguments are present). The default is ’1’.
Turn automatic indentation on/off.
Make magic commands automatic (without needing their first
character to be %). Type %magic at the IPython prompt for more
When a syntax error occurs after editing a file, automatically
open the file to the trouble causing line for convenient fixing.
Print the intial information banner (default on).
Execute the given command string, and set sys.argv to [’c’].
This is similar to the -c option in the normal Python
Size of the output cache (maximum number of entries to hold in
memory). The default is 1000, you can change it permanently in
your config file. Setting it to 0 completely disables the
caching system, and the minimum value accepted is 20 (if you
provide a value less than 20, it is reset to 0 and a warning is
issued). This limit is defined because otherwise you’ll spend
more time re-flushing a too small cache than working.
Gives IPython a similar feel to the classic Python prompt.
Color scheme for prompts and exception reporting. Currently
implemented: NoColor, Linux, and LightBG.
IPython can display information about objects via a set of
functions, and optionally can use colors for this, syntax
highlighting source code and various other elements. However,
because this information is passed through a pager (like ’less’)
and many pagers get confused with color codes, this option is
off by default. You can test it and turn it on permanently in
your ipythonrc file if it works for you. As a reference, the
’less’ pager supplied with Mandrake 8.2 works ok, but that in
RedHat 7.2 doesn’t.
Test it and turn it on permanently if it works with your system.
The magic function @color_info allows you to toggle this
interactively for testing.
Set to confirm when you try to exit IPython with an EOF
(Control-D in Unix, Control-Z/Enter in Windows). Note that using
the magic functions @Exit or @Quit you can force a direct exit,
bypassing any confirmation.
Show information about the loading process. Very useful to pin
down problems with your configuration files or to get details
about session restores.
IPython can use the deep_reload module which reloads changes in
modules recursively (it replaces the reload() function, so you
don’t need to change anything to use it). deep_reload() forces a
full reload of modules whose code may have changed, which the
default reload() function does not.
When deep_reload is off, IPython will use the normal reload(),
but deep_reload will still be available as dreload(). This
feature is off by default [which means that you have both normal
reload() and dreload()].
Which editor to use with the @edit command. By default, IPython
will honor your EDITOR environment variable (if not set, vi is
the Unix default and notepad the Windows one). Since this editor
is invoked on the fly by IPython and is meant for editing small
code snippets, you may want to use a small, lightweight editor
here (in case your default EDITOR is something like Emacs).
The name of your IPython configuration directory IPYTHONDIR.
This can also be specified through the environment variable
-log|l Generate a log file of all input. The file is named
ipython_log.py in your current directory (which prevents logs
from multiple IPython sessions from trampling each other). You
can use this to later restore a session by loading your logfile
as a file to be executed with option -logplay (see below).
Specify the name of your logfile.
Replay a previous log. For restoring a session as close as
possible to the state you left it in, use this option (don’t
just run the logfile). With -logplay, IPython will try to
reconstruct the previous working environment in full, not just
execute the commands in the logfile.
When a session is restored, logging is automatically turned on
again with the name of the logfile it was invoked with (it is
read from the log header). So once you’ve turned logging on for
a session, you can quit IPython and reload it as many times as
you want and it will continue to log its history and restore
from the beginning every time.
Caveats: there are limitations in this option. The history
variables _i*,_* and _dh don’t get restored properly. In the
future we will try to implement full session saving by writing
and retrieving a snapshot of the memory state of IPython. But
our first attempts failed because of inherent limitations of
Python’s Pickle module, so this may have to wait.
Print messages which IPython collects about its startup process
Automatically call the pdb debugger after every uncaught
exception. If you are used to debugging using pdb, this puts you
automatically inside of it after any call (either in IPython or
in code called by it) which triggers an exception which goes
-pydb Makes IPython use the third party "pydb" package as debugger,
instead of pdb. Requires that pydb is installed.
IPython can optionally use the pprint (pretty printer) module
for displaying results. pprint tends to give a nicer display of
nested data structures. If you like it, you can turn it on
permanently in your config file (default off).
Assume that your config file is ipythonrc-<name> (looks in
current dir first, then in IPYTHONDIR). This is a quick way to
keep and load multiple config files for different tasks,
especially if you use the include option of config files. You
can keep a basic IPYTHONDIR/ipythonrc file and then have other
’profiles’ which include this one and load extra things for
particular tasks. For example:
1) $HOME/.ipython/ipythonrc : load basic things you always want.
2) $HOME/.ipython/ipythonrc-math : load (1) and basic math-
3) $HOME/.ipython/ipythonrc-numeric : load (1) and Numeric and
Since it is possible to create an endless loop by having
circular file inclusions, IPython will stop if it reaches 15
Specify the string used for input prompts. Note that if you are
using numbered prompts, the number is represented with a ’\#’ in
the string. Don’t forget to quote strings with spaces embedded
in them. Default: ’In [\#]: ’.
Most bash-like escapes can be used to customize IPython’s
prompts, as well as a few additional ones which are IPython-
specific. All valid prompt escapes are described in detail in
the Customization section of the IPython HTML/PDF manual.
Similar to the previous option, but used for the continuation
prompts. The special sequence ’\D’ is similar to ’\#’, but with
all digits replaced dots (so you can have your continuation
prompt aligned with your input prompt). Default: ’ .\D.: ’
(note three spaces at the start for alignment with ’In [\#]’).
String used for output prompts, also uses numbers like
prompt_in1. Default: ’Out[\#]:’.
-quick Start in bare bones mode (no config file loaded).
Name of your IPython resource configuration file. normally
IPython loads ipythonrc (from current directory) or
IPYTHONDIR/ipythonrc. If the loading of your config file fails,
IPython starts with a bare bones configuration (no modules
loaded at all).
Use the readline library, which is needed to support name
completion and command history, among other things. It is
enabled by default, but may cause problems for users of X/Emacs
in Python comint or shell buffers.
Note that emacs ’eterm’ buffers (opened with M-x term) support
IPython’s readline and syntax coloring fine, only ’emacs’ (M-x
shell and C-c !) buffers do not.
Number of lines of your screen. This is used to control
printing of very long strings. Strings longer than this number
of lines will be sent through a pager instead of directly
The default value for this is 0, which means IPython will auto-
detect your screen size every time it needs to print certain
potentially long strings (this doesn’t change the behavior of
the ’print’ keyword, it’s only triggered internally). If for
some reason this isn’t working well (it needs curses support),
specify it yourself. Otherwise don’t change the default.
Separator before input prompts. Default ’0.
Separator before output prompts. Default: 0 (nothing).
Separator after output prompts. Default: 0 (nothing).
-nosep Shorthand for ’-separate_in 0 -separate_out 0 -separate_out2 0’.
Simply removes all input/output separators.
Allows you to upgrade your IPYTHONDIR configuration when you
install a new version of IPython. Since new versions may
include new command lines options or example files, this copies
updated ipythonrc-type files. However, it backs up (with a .old
extension) all files which it overwrites so that you can merge
back any custimizations you might have in your personal files.
Print version information and exit.
Select a specific version of wxPython (used in conjunction with
-wthread). Requires the wxversion module, part of recent
Mode for exception reporting. The valid modes are Plain,
Context, and Verbose.
- Plain: similar to python’s normal traceback printing.
- Context: prints 5 lines of context source code around each
line in the traceback.
- Verbose: similar to Context, but additionally prints the
variables currently visible where the exception happened
(shortening their strings if too long). This can potentially be
very slow, if you happen to have a huge data structure whose
string representation is complex to compute. Your computer may
appear to freeze for a while with cpu usage at 100%. If this
occurs, you can cancel the traceback with Ctrl-C (maybe hitting
it more than once).
It is possible to start an IPython instance inside your own Python
programs. In the documentation example files there are some
illustrations on how to do this.
This feature allows you to evalutate dynamically the state of your
code, operate with your variables, analyze them, etc. Note however
that any changes you make to values while in the shell do NOT propagate
back to the running code, so it is safe to modify your values because
you won’t break your code in bizarre ways by doing so.
IPython was written by Fernando Perez <email@example.com>, based on
earlier code by Janko Hauser <firstname.lastname@example.org> and Nathaniel Gray
<email@example.com>. This manual page was written by Jack Moffitt
<firstname.lastname@example.org>, for the Debian project (but may be used by others).
November 30, 2004 IPYTHON(1)