prevent emacs from splitting vertically?

My Mac has Emacs v22 and it only splits horizontally when I type ^x-2.

My Linux system has Emacs v24 and it splits vertically when Emacs thinks that's a better choice. The problem is, I don't want it to split that way. How do I prevent emacs from splitting vertically?

2 Answers

See the Emacs manual, node Window Choice. In particular, see user options split-height-threshold and split-width-threshold.

Specifically, add this to your .emacs file:

(setq split-width-threshold nil)

For splitting horizontally use C-x 3. You can find more options here.