5.40 How can I go to a certain line given its number?

Are you sure you indeed need to go to a line by its number? Perhaps all you want is to display a line in your source file for which a compiler printed an error message? If so, compiling from within Emacs using the M-x compile and M-x recompile commands is a much more effective way of doing that. Emacs automatically intercepts the compile error messages, inserts them into a special buffer called *compilation*, and lets you visit the locus of each message in the source. Type C-x ` to step through the offending lines one by one (you can also use M-g M-p and M-g M-n to go to the previous and next matches directly). Click mouse-2 or press RET on a message text in the *compilation* buffer to go to the line whose number is mentioned in that message.

But if you indeed need to go to a certain text line, type M-g M-g (which is the default binding of the goto-line function). Emacs will prompt you for the number of the line and go to that line.

You can do this faster by invoking goto-line with a numeric argument that is the line’s number. For example, C-u 286 M-g M-g will jump to line number 286 in the current buffer.