Nano

Nano is a very useful text editor. Even if you don't use a command line that often, and never bothered to learn vim or emacs, nano will always be there and is simple enough.

Syntax highlight

Nano can extended to highlight octave code. The following can be added to ~/.nanorc:

# Octave syntax colors
syntax "octave" "\.m$" "\.octaverc$"

# keywords
color brightyellow "(case|catch|do|else(if)?|for|function|if|otherwise|switch|try|until|unwind_protect(_cleanup)?|vararg(in|out)|while)"
color brightyellow "end(_try_catch|_unwind_protect|for|function|if|switch|while)?"
color magenta "(break|continue|return)"

# storage-type
color green "(global|persistent|static)"
# data-type
color green "(cell(str)?|char|double|(u)?int(8|16|32|64)|logical|single|struct)"

# embraced
color brightred start="\(" end="\)"  # this line needs to be fixed to work properly in all cases
color blue start="\[|\{" end="\]|\}"

# strings
color yellow ""(\\.|[^\"])*"|'(\\.|[^\"])*'"

# comments
color brightblue "#.*|%.*"

Alternatively, it can be an individual file available system-wide such as /usr/share/nano/octave.nanorc which can then be included in /etc/nanorc (again, system-wide), or in ~/.nanorc with

include "/usr/share/nano/octave.nanorc"