Files of type TEXT contain ASCII characters only and they can be viewed and edit with any TEXT editor. There are many freeware text editors available, such as TextWrangler, or BBEdit for Macintosh OS, NoteTab Lite on Windows, or GNU Emacs on Unix Systems.
A common difficulty arises as textfiles are not all the same. The main difference concerns the fact that different lines in the file are seperated by different line endings on different computer platforms, namely by a "carriage return" (<cr>, CR, hexadecimal character code $0D) on Macintosh systems, a "line feed" (<lf>, LF, $0A) on Unix systems, and a "carriage return" <cr> and a "line feed" <lf> on Windows/DOS-based systems.