Updated After the discussion of modes and installing packages, we can give some direct practical trick, courtesy of M-x all-things-emacs; note, I have updated this since, to work with Emacs 23.
Sometimes it is very useful to see the line numbers in a file – that is, on the left side of each line, the line number is shown. A use case for this is when showing something to a group of people. In that case, zooming and full-screen mode might also be useful.
The traditional way in emacs is to use setnu.el, but it's quite slow for big
files. Fortunately, there is
linum-mode; in your .emacs, add:
(autoload 'linum-mode "linum" "toggle line numbers on/off" t) (global-set-key (kbd "C-<f5>") 'linum-mode)
Now, you can quickly show/hide linenumbers by pressing
You can also turn it on for specific modes; for example, to turn on line numbers when editing Perl code:
(add-hook 'perl-mode-hook (lambda() (linum-mode 1)))