GNU Info

(emacs)Examining

---

Next: Easy Customization Up: Variables

---

Enter node , (file) or (file)node

Examining and Setting Variables
-------------------------------

`C-h v VAR <RET>'
     Display the value and documentation of variable VAR
     (`describe-variable').

`M-x set-variable <RET> VAR <RET> VALUE <RET>'
     Change the value of variable VAR to VALUE.

   To examine the value of a single variable, use `C-h v'
(`describe-variable'), which reads a variable name using the
minibuffer, with completion.  It displays both the value and the
documentation of the variable.  For example,

     C-h v fill-column <RET>

displays something like this:

     fill-column's value is 70
     
     Documentation:
     *Column beyond which automatic line-wrapping should happen.
     Automatically becomes buffer-local when set in any fashion.

The star at the beginning of the documentation indicates that this
variable is a user option.  `C-h v' is not restricted to user options;
it allows any variable name.

   The most convenient way to set a specific user option is with `M-x
set-variable'.  This reads the variable name with the minibuffer (with
completion), and then reads a Lisp expression for the new value using
the minibuffer a second time.  For example,

     M-x set-variable <RET> fill-column <RET> 75 <RET>

sets `fill-column' to 75.

   `M-x set-variable' is limited to user option variables, but you can
set any variable with a Lisp expression, using the function `setq'.
Here is a `setq' expression to set `fill-column':

     (setq fill-column 75)

   To execute an expression like this one, go to the `*scratch*'
buffer, type in the expression, and then type `C-j'.  Note: Lisp
Interaction.

   Setting variables, like all means of customizing Emacs except where
otherwise stated, affects only the current Emacs session.