Use the desktop library to save the state of Emacs from one session
to another. Once you save the Emacs desktop—the buffers,
their file names, major modes, buffer positions, and so on—then
subsequent Emacs sessions reload the saved desktop. By default,
the desktop also tries to save the frame and window configuration.
To disable this, set
(See that variable’s documentation for some related options
that you can customize to fine-tune this behavior.)
Information about buffers visiting remote files is not saved by
default. Customize the variable
When the desktop restores the frame and window configuration, it
uses the recorded values of frame parameters, disregarding any
settings for those parameters you have in your init file (see The Emacs Initialization File). This means that frame parameters such as fonts and faces for
the restored frames will come from the desktop file, where they were
saved when you exited your previous Emacs session; any settings for
those parameters in your init file will be ignored. To disable this,
customize the value of
frameset-filter-alist to filter out the
frame parameters you don’t want to be restored.
You can save the desktop manually with the command M-x
desktop-save. You can also enable automatic saving of the desktop
when you exit Emacs, and automatic restoration of the last saved
desktop when Emacs starts: use the Customization buffer (see Easy Customization Interface) to set
t for future
sessions, or add this line in your init file (see The Emacs Initialization File):
If you turn on
desktop-save-mode in your init file, then when
Emacs starts, it looks for a saved desktop in the current directory.
(More precisely, it looks in the directories specified by
desktop-path, and uses the first desktop it finds.)
Thus, you can have separate saved desktops in different directories,
and the starting directory determines which one Emacs reloads. You
can save the current desktop and reload one saved in another directory
by typing M-x desktop-change-dir. Typing M-x
desktop-revert reverts to the desktop previously reloaded.
Specify the option ‘--no-desktop’ on the command line when you
don’t want it to reload any saved desktop. This turns off
desktop-save-mode for the current session. Starting Emacs with
the ‘--no-init-file’ option also disables desktop reloading,
since it bypasses the init file, where
usually turned on.
By default, all the buffers in the desktop are restored in one go.
However, this may be slow if there are a lot of buffers in the
desktop. You can specify the maximum number of buffers to restore
immediately with the variable
remaining buffers are restored lazily, when Emacs is idle.
Type M-x desktop-clear to empty the Emacs desktop. This kills
all buffers except for internal ones, and clears the global variables
desktop-globals-to-clear. If you want this to
preserve certain buffers, customize the variable
desktop-clear-preserve-buffers-regexp, whose value is a regular
expression matching the names of buffers not to kill.
If you want to save minibuffer history from one session to
another, use the
While Emacs runs with
desktop-save-mode turned on, it by
default auto-saves the desktop whenever any of it changes. The
desktop-auto-save-timeout determines how frequently
Emacs checks for modifications to your desktop.
The file in which Emacs saves the desktop is locked while the
session runs, to avoid inadvertently overwriting it from another Emacs
session. That lock is normally removed when Emacs exits, but if Emacs
or your system crashes, the lock stays, and when you restart Emacs, it
will by default ask you whether to use the locked desktop file. You
can avoid the question by customizing the variable
desktop-load-locked-desktop to either
nil, which means
never load the desktop in this case, or
t, which means load the
desktop without asking.
When Emacs starts in daemon mode, it cannot ask you any questions,
so if it finds the desktop file locked, it will not load it, unless
t. Note that restoring
the desktop in daemon mode is somewhat problematic for other reasons:
e.g., the daemon cannot use GUI features, so parameters such as frame
position, size, and decorations cannot be restored. For that reason,
you may wish to delay restoring the desktop in daemon mode until the
first client connects, by calling
desktop-read in a hook
function that you add to
(see Creating Frames in The Emacs Lisp Reference Manual).