Elisp: Get System Info

By Xah Lee. Date: . Last updated: .

Get Operating System Type

Here's how to find out what operating system emacs is running on.

(cond
 ((eq system-type 'windows-nt)
  (progn
    (message "Microsoft Windows")))
 ((eq system-type 'darwin)
  (progn
    (message "Mac OS X")))
 ((eq system-type 'gnu/linux)
  (progn
    (message "Linux"))))

Get Emacs Version

emacs-version
Value is a dotted string.

MAJOR.MINOR

or

MAJOR.MINOR.MICRO

emacs-major-version
Value is a integer, emacs major version number.
emacs-minor-version
Value is a integer, emacs minor version number. Sample value: 5

Compare Version String

version<
Compares emacs version string. 
(if (version< emacs-version "27.1")
    (message "too old")
  (message "good"))
version<=
Compares emacs version string.
version=
Compares emacs version string.

Get Host Name, User Name

system-name
Returns the host name.
user-login-name
Returns user login name.

Get Init File Path

user-emacs-directory
Variable. Init file dir.
user-init-file
Variable. Init file path.

Reference

Check Emacs Version