configuration, either by customizing the {var}`server-mode`
variable, or by adding `(server-start)` to
{file}`~/.emacs.d/init.el`.

To start the daemon, execute the following:
```ShellSession
$ nixos-rebuild switch  # to activate the new configuration.nix
$ systemctl --user daemon-reload        # to force systemd reload
$ systemctl --user start emacs.service  # to start the Emacs daemon
```
The server should now be ready to serve Emacs clients.

### Starting the client {#module-services-emacs-starting-client}

Ensure that the Emacs server is enabled, either by customizing the
{var}`server-mode` variable, or by adding
`(server-start)` to {file}`~/.emacs`.

To connect to the Emacs daemon, run one of the following:
```
emacsclient FILENAME
emacsclient --create-frame  # opens a new frame (window)
emacsclient --create-frame --tty  # opens a new frame on the current terminal
```

### Configuring the {var}`EDITOR` variable {#module-services-emacs-editor-variable}

<!--<title>{command}`emacsclient` as the Default Editor</title>-->

If [](#opt-services.emacs.defaultEditor) is
`true`, the {var}`EDITOR` variable will be set
to a wrapper script which launches {command}`emacsclient`.

Any setting of {var}`EDITOR` in the shell config files will
override {var}`services.emacs.defaultEditor`. To make sure
{var}`EDITOR` refers to the Emacs wrapper script, remove any
existing {var}`EDITOR` assignment from
{file}`.profile`, {file}`.bashrc`,
{file}`.zshenv` or any other shell config file.

If you have formed certain bad habits when editing files, these can be
corrected with a shell alias to the wrapper script:
```
alias vi=$EDITOR
```

### Per-User Enabling of the Service {#module-services-emacs-per-user}

In general, {command}`systemd` user services are globally enabled
by symlinks in {file}`/etc/systemd/user`. In the case where
Emacs daemon is not wanted for all users, it is possible to install the
service but not globally enable it:
```nix
{
  services.emacs.enable = false;
  services.emacs.install = true;
}
```

To enable the {command}`systemd` user service for just the
currently logged in user, run:
```
systemctl --user enable emacs
```
This will add the symlink
{file}`~/.config/systemd/user/emacs.service`.

## Configuring Emacs {#module-services-emacs-configuring}

If you want to only use extension packages from Nixpkgs, you can add
`(setq package-archives nil)` to your init file.

After the declarative Emacs package configuration has been tested,
previously downloaded packages can be cleaned up by removing
{file}`~/.emacs.d/elpa` (do make a backup first, in case you
forgot a package).

<!--
      todo: is it worth documenting customizations for
      server-switch-hook, server-done-hook?
  -->

### A Major Mode for Nix Expressions {#module-services-emacs-major-mode}

Of interest may be {var}`melpaPackages.nix-mode`, which
provides syntax highlighting for the Nix language. This is particularly
convenient if you regularly edit Nix files.

### Accessing man pages {#module-services-emacs-man-pages}

You can use `woman` to get completion of all available
man pages. For example, type `M-x woman <RET> nixos-rebuild <RET>.`