[Edit 06/12/2011] Sorry for not giving you new content, but was a difficult week on a trip. So I’m re-editing this old post. I’m also using this option to give you the link of this other way to spell check your documents on Linux.

Use vim to spell check your documents.[/Edit].

To check the spell of a text file, maybe written with vi/vim, emacs, or any other text editor even sed, awk or a here-document, you may use aspell.

From the man page:

aspell is a utility program that connects to the Aspell library so that it can function as an ispell -a replacement, as an independent spell checker, as a test utility to test out Aspell library features, and as a utility for managing dictionaries used by the library.
The Aspell library contains an interface allowing other programs direct access to it’s functions and therefore reducing the complex task of spell checking to simple library calls. The default library does not contain dictionary word lists. To add language dictionaries, please check your distro first for modified dictionaries, otherwise look here for base language dictionaries http://aspell.net.

So, you may write your text file, with any editor, and once done, enter this command, for example imagine you have written test.txt

Here is what the file has:

helo, heri is a documet wit some erors to be checed by Aspell

Now run aspell.

aspell check test.txt

This is the screen you will see: