GNU Aspell is a Free and Open Source spell checker for text files from the command line
GNU Aspell is a Free and Open Source spell checker designed to eventually replace Ispell. It can either be used as a library or as an independent spell checker. Its main feature is that it does a superior job of suggesting possible replacements for a misspelt word than just about any other spell checker out there for the English language. Unlike Ispell, Aspell can also easily check documents in UTF-8 without having to use a special dictionary. Aspell will also do its best to respect the current locale setting. Other advantages over Ispell include support for using multiple dictionaries at once and intelligently handling personal dictionaries when more than one Aspell process is open at once.
In my case, this was already installed and ready to sue on Manjaro Linux. You'd really use this if you were editing plain text files using Emacs, Pine or VIM for example or similar. If you're using a GUI editor like Kate then a spell checker is already built in.
ASpell's website is at http://aspell.net/.
A video will best show how Aspell works at http://bit.ly/2EN8Jj3