Starting and stopping IDLE varies with your operating system. Generally, all of the variations are nearly identical, and differ only in minor details.

Windows. There are several ways to start IDLE in Windows. You can use IDLE (Python GUI) from the Python2.5 menu on the Start menu.

You can also run IDLE from the command prompt. This requires two configuration settings in Windows.

You can quit IDLE by using the Quit menu item under the File menu.

Mac OS. In the Mac OS, if you've done an upgrade, you may find the IDLE program in the Python 2.5 folder in your Applications folder. You can double-click this icon to run IDLE.

You can always find IDLE in the directory /System/Library/Frameworks/Python.framework/Versions/Current/bin. Generally, this is on your PATH, and you can type the command idle in a Terminal window to start IDLE. The idle2.5 icon is a document, not an applicaction, and can't easily be put into your Dock.

You can create your own Applescript icon to run the IDLE shell script. This requires a single line of Applescript:

do shell script "/System/Library/Frameworks/Python.framework/Versions/Current/bin/idle" 

When you run IDLE from the icon, you'll notice that two windows are opened: a Python Shell window and a Console window. The Console window isn't used for much.

When you run IDLE from the Terminal window, no console window is opened. The Terminal window is the Python console.

You can quit IDLE by using the Quit menu item under the File menu. You can also quit by using the Quit Idle menu item under the Idle menu.

Since the Macintosh keyboard has a command key, ⌘, as well as a control key, ctrl, there are two keyboard mappings for IDLE. You can use the Configure IDLE... item under the Options menu to select any of the built-in Key Sets. Selecting the IDLE Classic Mac settings may be more comfortable for Mac OS users.

GNU/Linux. We'll avoid the GNOME and KDE subtleties. Instead, we'll focus on running IDLE from the Terminal tool. Since the file path is rather long, you'll want to edit your .profile (or .bash_profile) to include the following alias definition.

alias idle='env python /usr/lib/python2.5/idlelib/idle.py &'

This allows you to run IDLE by entering the command idle in a Terminal window.

You can quit IDLE by using the Exit menu item under the File menu.

Initially, you'll see the following greeting from IDLE.

Python 2.5.1 (r251:54863, Oct  5 2007, 21:08:09) 
[GCC 4.0.1 (Apple Inc. build 5465)] on darwin
Type "copyright", "credits" or "license()" for more information.

    ****************************************************************
    Personal firewall software may warn about the connection IDLE
    makes to its subprocess using this computer's internal loopback
    interface.  This connection is not visible on any external
    interface and no data is sent to or received from the Internet.
    ****************************************************************
    
IDLE 1.2.1      
>>> 

The personal firewall notification is a reminder that IDLE uses Internetworking Protocols (IP) as part of its debugger. If you have a software firewall on you development computer, and the firewall software complains, you can allow the connection.

IDLE has a simple and relatively standard text editor, which does Python syntax highlighting. It also has a Python Shell window which manages an interactive Python session. You will see that the Python Shell window has a Shell and a Debug menu.

When you use the New menu item in the File menu, you'll see a file window, which has a slightly different menu bar. A file window has name which is a file name (or untitled), and two unique menus, a Run and a Format menu.

Generally, you'll use IDLE in two ways:

The Python Shell window in IDLE presents a >>> prompt. At this prompt, you can enter Python expressions or statements for evaluation. This window has a complete command history, so you can use the up arrow to select a previous statement and make changes.

You can refer back to Command-Line Interaction; those interactions will look and behave the same in IDLE as they do on the command line.

The Shell Window is essentially the command-line interface wrapped in a scrolling window. The IDLE interface, however, provides a consistent working environment, which is independent of each operating system's command-line interface.

The Shell and Debug menus provides functions you'll use when developing larger programs. For our first steps with Python, we won't need either of these menus. We'll talk briefly about the functions, but can't really make use of them until we've learned more of the language.

The Shell Menu. The Shell menu is used to restart the Python interpreter, or scroll back through the shell's log to locate the most recent restart. This is important when you are developing a module that is used as a library. When you change that module, you need to reset the shell so that the previous version is forgotten and the new version can be imported into a fresh, empty interpreter.

Generally, being able to work interactively is the best way to develop working programs. It encourages you to create tidy, simple-looking components which you can exercise directly.

The Debug Menu. The Debug menu provides some handy tools for watching how Python executes a program.

Each file window in IDLE is a simple text editor with two additional menus. The Format menu has a series of items for fairly common source text manipulations. The formatting operations include indenting, commenting, handling tabs and formatting text paragraphs.

The Run menu makes it easy to execute the file you are editing.