Installing Emacs
Getting Emacs 24
Emacs 24 still hasn't been released, but it's probably the best version of Emacs you can get.
OS X
Obtaining Emacs 24 on OS X is really simple. There are two popular ways to do it. The first is to simply download a pretest (or a nightly build) from Emacs for OSX. Probably the best option would be to get the latest pretest from here.
The second easy way to obtain Emacs 24 is via homebrew. Just type the following incantation in your shell and you’re done:
$ brew install emacs --cocoa --use-git-head --HEAD
$ cp -r /usr/local/Cellar/emacs/HEAD/Emacs.app /Applications/
The second step is optional, but it’s recommended if you like to start Emacs from the launchpad or from Spotlight.
Chances are good you have an older version of Emacs installed by default with OS X. It's suggested you to remove that older Emacs version to avoid conflicts with the new one. Do this:
$ sudo rm /usr/bin/emacs
$ sudo rm -rf /usr/share/emacs
That’s all folk! You may now proceed to the configuration section.
Linux
Given that Linux is more or less the home os of Emacs it presents us with the most installation options. Of course, you can build Emacs from source on every distribution out there, but why bother to do so? Using the distribution’s package manager is a better idea for many reasons - you don’t need to install a build chain and lots of dev libraries, you get updated versions when they are released and you get automated dependency manager, just to name a few.
That said, few distributions include in their primary repositories builds of Emacs 24. Luckily there are some unofficial repos that come to the rescue.
Debian users should look no further than the amazing emacs-snapshot APT repo. You’ll find installation instructions there for all the relevant Debian versions out there. High quality, highly recommended builds! After you’ve added the repo you can install Emacs 24 with the following command:
$ sudo apt-get install emacs-snapshot
Ubuntu users have easy access to Emacs 24 as well:
$ sudo apt-add-repository ppa:cassou/emacs
$ sudo apt-get install emacs-snapshot
Gentoo users have even less to do, since Emacs 24 can be obtained via the emacs-vcs package in portage, as noted in the official Emacs on Gentoo page.
Arch Linux users can install Emacs 24 from the Arch User Repository (AUR) with the package emacs-bzr.
Unfortunately they don't seem to be any prebuilt Emacs 24 packages for any of the RPM distros (Fedora, SUSE, Mandriva, etc). Since, I’m Debian user I have to admit that I didn’t look that far, but the source installation is not particularly hard and is always an option.
Windows
There are several ways to obtain precompiled Emacs 24 binaries if you’re a Windows users. The most popular are EmacsW32, Emacs for Windows and of course the official Emacs Windows builds.