IDL provides installed, browser-based IDL Help. This topic covers how to open the installed IDL Help from both the command line and in the Workbench, tips for searching, and how to access IDL Help on the internet.

Opening IDL Help

You can start IDL Help in the following ways.

In the IDL Interface

  • Type the "?" command at the IDL prompt to bring up the main help system page.
  • Select Help > Help Contents from the IDL Workbench menu.

Additionally, using the "?" followed by a function name opens the help system inside the topic for that function. For example, typing the following at the IDL prompt:


brings up IDL Help open to the ARROW topic.

On Windows

If the defaults were selected during installation, start IDL Help from the Start> Programs > IDL x.x > Help > IDL Help menu.

On Linux/Mac:

Start IDL Help with the idlhelp command in a terminal window.

Tips for Searching IDL Help

The IDL Help installed on your computer includes a feature for search on text found in the documentation. The search box is located in the upper right corner of your Help screen.

Here are a few tips for using the search functionality:

  • Single-word searches work best. For example, type "syntax" rather than "IDL syntax" to bring up a list of pages containing the word "syntax".
  • If searching for special character ("+", for example), surround the special character in double-quotes in the search box: "+".
  • Searching is case-insensitive.

Documentation Center

A portion of the IDL Help and PDF files for the most recent IDL release can also be found on the Documentation Center on the company website.