Department of Computing Imperial College London
Text editors

The following text editors are available on the Linux machines.

xemacs
XEmacs is a version of Emacs, compatible with and containing many improvements over GNU Emacs. The primary documentation of XEmacs is in the XEmacs Reference Manual, which you can read on-line using Info, a subsystem of XEmacs. Please look there for complete and up-to-date documentation. There is an extensive interactive help facility. CTRL-h enters the Help facility. Help Tutorial (CTRL-h t) requests an interactive tutorial which can teach beginners the fundamentals of XEmacs in a few minutes.

emacs is a similar editor and the above information on documentation and help also applies to this.

nedit
NEdit is a GUI style editor for plain text files. It provides mouse based editing and a streamlined editing style, based on popular Macintosh and MS Windows editors, for users of X workstations and X terminals.

xedit
This is a simple X-based editor, it has limited functionality (find, search, replace).

pico
pico is a very simple display oriented text editor, the same one that the pine mail client uses, but split out.

vi
vi (visual) is a display oriented text editor based on ex. It is a useful editor to know, since it is available on the majority of Unix machines. It is also extremely fast. In addition to the usual online manual page this page, although for SunOS rather than Linux, includes a useful command summary.


Setting your default editor

There are two environment variables that are used to set your default editor: EDITOR and VISUAL.
VISUAL
This is your preferred full screen editor.
EDITOR
This is your preferred terminal editor.
The normal practice is to set them both to the same editor, but this is not essential. For example, adding the following lines to your .cshrc file will set your default editor to vi when using a dumb text-only terminal, or to GNU Emacs when running on an Xterminal:
	if( $TERM == xterms || $TERM == xterm ) then
		# On an Xterminal use XEmacs for full screen editor
		setenv VISUAL xemacs 
		# Use vi for terminal editor.
		setenv EDITOR vi 
	else
		# On non-X terminals use vi
		setenv EDITOR vi
		setenv VISUAL vi	
	endif


Backup files

Most editors create backup files; these are identified by a filename suffix (e.g. .BAK), and contain the version that existed before the last save. If you are happy with the modifications that you made to the file, then this backup file can be deleted. Backup files tend to have names like:

	<filename>.BAK
<filename>.bak
<filename>~
<filename>%

Some editors create autosave backup files, these are stored separately from the original, so as not to over-write it. They tend to be of this format:

	#<filename>#

© CSG / 2003 / help@doc.ic.ac.uk