MA10126

Essential Unix

5. Text editors

In Windows, there is a simple editor called Notepad (under Accessories), as well as fancier ones such as WordPad and Word. Unix also has a range of different editor packages for creating and modifying text files. Some of these are line editors (where you work on one line at a time, just like Unix itself), and others are screen editors (where you see a whole page of text). The Unix help pages from BUCS describe some of these editors. Here we will introduce you to the simplest-to-use screen editor, called pico.

You start the editor by typing

pico filename

Thus, to use pico to create a file called applic (or to open an existing file called applic for editing), type

pico applic

The Unix window now displays the first screenful of the file (or a blank screen if the file is new), and helpfully lists the most useful commands at the bottom. You insert text by simply typing in the screen. The commands are issued by using control keys, i.e. by holding down the Control key while pressing the relevant letter key (remember that you use ctrl-c to end execution of a command). The main commands are:

ctrl-g will display the help pages (which are unusually clear and concise, for Unix)

ctrl-v will move down to the next page

ctrl-o will save the current file, without exiting from the editor

ctrl-x will exit the editor. You are first prompted whether you want to save the file, and if so what name you want to give it.

It’s as simple as that. Press ctrl-g and read through the other commands. Try creating files and saving them, then using cat to display their contents.

There is a more powerful editor called emacs which uses drop-down menus like in Windows, instead of control keys. In emacs, your file is read into a buffer, where you edit it. When you have finished, you need to choose “save buffer” from the File menu before exiting. Try typing

emacs applic

and explore the different menus. BUCS has a guide to emacs at

http://www.bath.ac.uk/bucs/docs/ub-4-3.shtml

and guides to simpler editors such as ed and vi at

http://www.bath.ac.uk/bucs/docs/ub-4-1.shtml

You can use which ever editor you wish, so find out which one you like best.

There will be an exercise involving pico at the end of these notes. Before getting there, there are a couple of miscellaneous features to tell you about – click on Miscellany below…