Emacs is my favorite text editor and I use it as the main one for composing my blog. However, sometimes when I’m typing too fast and I’m lazy to proofread my article to some minor spelling error. Now I find a built-in solution in Emacs to help me automatically find any spelling errors in my article.

Emacs is shipped with flyspell-mode and ispell, which use a command line program for check the spelling. In most GNU/Linux distros, these programs are pre-installed in the OS so you don’t need to do anything in order to use flyspell-mode, just type M-x and flyspell-mode.

However, MacOS is not shipped with any spell checker program so you will receive the error Searching for program: No such file or directory when you try to activate flyspell-mode in Emacs. We need to configure a bit for Emacs on MacOS to run properly.

First, you need to install aspell, a spell checker program from macports. If you’re not familiar with macports, have a look at this post MacPorts - The MacOS package manager. Install aspell from macports using this command

$ sudo port install aspell

Next, you need to install the English dictionary for aspell. There are also several available languages here, just replace en with the language code that you want to install

$ sudo port install aspell-dict-en

Finally, add this to your .emacs to specify the path to aspell

(setq ispell-program-name "/opt/local/bin/aspell")

Now, when you want to use it, simply type M-x flyspell-mode or ispell. You can type flyspell-buffer to re-check the whole buffer.