Subsections

- Special Threading Options
- Regular Options

# Command-line use

You start IPython with the command:

`$ ipython [options] files`

If invoked with no options, it executes all the files listed in sequence and drops you into the interpreter while still acknowledging any options you may have set in your ipythonrc file. This behavior is different from standard Python, which when called as `python -i` will only execute one file and ignore your configuration setup.

Please note that some of the configuration options are not available at the command line, simply because they are not practical here. Look into your ipythonrc configuration file for details on those. This file typically installed in the `$HOME/.ipython` directory. For Windows users, `$HOME` resolves to `C:\\Documents and Settings\\YourUserName` in most instances. In the rest of this text, we will refer to this directory as `IPYTHONDIR`.

##
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 initial- ization of ipython itself, before the normal option-handling mechanism is active.

- [`-gthread, -qthread, -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 Qt and WXPython toolkits, and for the matplotlib library.
- [ ]With any of the first three 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 three provide essentially the same functionality, respectively for GTK, QT 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 mat plotlib library (`http://matplotlib.sourceforge.net`), allowing interactive usage of any of its backends as defined in the user's `~/.matplotlib/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/wthread` options, and `-pylab` (if matplotlib is configured to use GTK, Qt or WX), will normally block Tk graphical interfaces. This means that when either 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`, `-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 2/3), 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 available.
- [ ]There is unfortunately no way for IPython to determine at run time whether `-tk` will work reliably or not, so you will need to do some experiments before relying on it for regular work.

##
Regular Options

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 example for more details on what the options do. Options given at the command line 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.

- [`-help`:]print a help message and exit.
- [`-pylab:`]this can only be given as the first option passed to IPython (it will have no effect in any other position). It adds special support for the matplotlib library (http://matplotlib.sourceforge.net `http://matplotlib.sourceforge.net`), allowing interactive usage of any of its backends as defined in the user's `.matplotlibrc` file. It automatically activates GTK 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. See Sec. 15 for more details.
- [`-autocall`]`<val>:` 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'.
- [`-[no]autoindent:`]Turn automatic indentation on/off.
- [`-[no]automagic:`]make magic commands automatic (without needing their first character to be `%`). Type `%magic` at the IPython prompt for more information.
- [`-[no]autoedit_syntax:`]When a syntax error occurs after editing a file, automatically open the file to the trouble causing line for convenient fixing.
- [`-[no]banner:`]Print the initial information banner (default on).
- [`-c <command>:`]execute the given command string, and set sys.argv to `['c']`. This is similar to the `-c` option in the normal Python interpreter.
- [`-cache_size|cs <n>:`]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.
- [`-classic|cl:`]Gives IPython a similar feel to the classic Python prompt.
- [`-colors <scheme>:`]Color scheme for prompts and exception reporting. Currently implemented: NoColor, Linux and LightBG.
- [`-[no]color_info:`]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.
- [`-[no]debug`:]Show information about the loading process. Very useful to pin down problems with your configuration files or to get details about session restores.
- [`-[no]deep_reload:`]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()`].
- [`-editor <name>`:]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).
- [`-ipythondir <name>:`]name of your IPython configuration directory `IPYTHONDIR`. This can also be specified through the environment variable `IPYTHONDIR`.
- [`-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).
- [`-logfile|lf <name>:`]specify the name of your logfile.
- [`-logplay|lp <name>:`]you can 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.
- [`-[no]messages:`]Print messages which IPython collects about its startup process (default on).
- [`-[no]pdb`:]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 uncaught.
- [`-[no]pprint:`]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).
- [`-profile|p`]`<name>:` 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-related modules.
- [`` ]3. `$HOME/.ipython/ipythonrc-numeric` : load (1) and Numeric and plotting modules.
- [ ]Since it is possible to create an endless loop by having circular file inclusions, IPython will stop if it reaches 15 recursive inclusions.
- [`-prompt_in1|pi1 <string>:`]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 [\#]:`'. Sec. 7.2 discusses in detail all the available escapes to customize your prompts.
- [`-prompt_in2|pi2 <string>:`]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 [\#]`').
- [`-prompt_out|po <string>:`]String used for output prompts, also uses numbers like `prompt_in1`. Default: '`Out[\#]:`'
- [`-quick`:]start in bare bones mode (no config file loaded).
- [`-rcfile <name>:`]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).
- [`-[no]readline`:]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 X/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.
- [`-screen_length|sl <n>:`]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 printed.
- [ ]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.
- [`-separate_in|si <string>:`]separator before input prompts. Default: '`\n`'
- [`-separate_out|so <string>`:]separator before output prompts. Default: nothing.
- [`-separate_out2|so2 <string>:`]separator after output prompts. Default: nothing.
- [ ]For these three options, use the value 0 to specify no separator.
- [`-nosep:`]shorthand for `'-SeparateIn 0 -SeparateOut 0 -SeparateOut2 0'`. Simply removes all input/output separators.
- [`-upgrade`:]allows you to upgrade your `IPYTHONDIR` configuration when you install a new version of IPython. Since new versions may include new command line 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 customizations you might have in your personal files.
- [`-Version:`]print version information and exit.
- [`-wxversion <string>:`]Select a specific version of wxPython (used in conjunction with `-wthread`). Requires the wxversion module, part of recent wxPython distributions
- [`-xmode <modename>:`]Mode for exception reporting.
- [ ]Valid modes: 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).