If you need to edit the contents of a text file,
you can choose from several
text editors:
If you are a beginner, see
`Using the pico text editor'.
Pico is simple to learn and has good online help facilities.
Real Programmers (tm) use
emacs. Although
this is a full-featured text editor, the basic features are
easy to learn, there is an excellent online tutorial, it
runs everywhere, and it will grow with you even after decades of use.