How to use the command 'emacsclient' (with examples)

Emacsclient is a command-line utility that allows users to open files in an existing Emacs server. It is primarily used to interact with Emacs through the terminal and perform various operations such as opening files, evaluating commands, and manipulating buffers. This article will provide step-by-step examples of different use cases for the ’emacsclient’ command.

Use case 1: Open a file in an existing Emacs server (using GUI if available)

Code:

emacsclient path/to/file

Motivation: This use case is suitable when you want to open a specific file in an existing Emacs server. It gives you the ability to use the graphical interface of Emacs if available.

Explanation:

• ’emacsclient’: Invokes the ’emacsclient’ command to open a file in an existing Emacs server.
• ‘path/to/file’: Represents the path of the file you want to open in Emacs.

Example output: The specified file will be opened in a new buffer within the Emacs server.

Use case 2: Open a file in console mode (without an X window)

Code:

emacsclient --no-window-system path/to/file

Motivation: If you prefer working with Emacs in console mode without any graphical interface, this use case is preferable. It allows you to open a file within the Emacs server in a terminal-only environment.

Explanation:

• ’emacsclient’: Initiates the ’emacsclient’ command.
• ‘–no-window-system’: Instructs Emacs to operate in console mode without an X window.
• ‘path/to/file’: Specifies the file you want to open in Emacs.

Example output: The file specified will be opened in the Emacs server, displaying it within the terminal.

Use case 3: Open a file in a new Emacs window

Code:

emacsclient --create-frame path/to/file

Motivation: If you want to open a file in a new Emacs window, this use case is suitable. It allows you to work on multiple files simultaneously while keeping them organized within separate frames.

Explanation:

• ’emacsclient’: Executes the ’emacsclient’ command.
• ‘–create-frame’: Instructs Emacs to open the file in a new frame.
• ‘path/to/file’: Specifies the file you want to open in Emacs.

Example output: A new Emacs frame will be created, and the specified file will be opened in the new frame.

Use case 4: Evaluate a command, printing the output to stdout, and then quit

Code:

emacsclient --eval '(command)'

Motivation: This use case allows you to evaluate a specific command within Emacs, print the output to stdout, and then exit. It is useful for automation purposes or for executing custom Emacs commands.

Explanation:

• ’emacsclient’: Activates the ’emacsclient’ command.
• ‘–eval’: Instructs Emacs to evaluate the given command.
• ‘(command)’: Represents the command you want to evaluate within Emacs.

Example output: The output of the evaluated command will be printed to stdout.

Use case 5: Specify an alternative editor in case no Emacs server is running

Code:

emacsclient --alternate-editor editor path/to/file

Motivation: If no Emacs server is running, this use case allows you to specify an alternative editor to open the file. It provides flexibility and ensures that you can still work on files even if Emacs is not available.

Explanation:

• ’emacsclient’: Executes the ’emacsclient’ command.
• ‘–alternate-editor’: Specifies an alternative editor to use if no Emacs server is running.
• ’editor’: Represents the alternative editor you want to use.
• ‘path/to/file’: Specifies the file you want to open.

Example output: If no Emacs server is available, the specified alternative editor will be used to open the file.

Use case 6: Stop a running Emacs server and all its instances, asking for confirmation on unsaved files

Code:

emacsclient --eval '(save-buffers-kill-emacs)'

Motivation: This use case allows you to stop a running Emacs server and all its instances while asking for confirmation if there are any unsaved files. It helps in managing multiple instances and ensuring that all files are saved before exiting.

Explanation:

• ’emacsclient’: Initiates the ’emacsclient’ command.
• ‘–eval’: Instructs Emacs to evaluate the given command.
• ‘(save-buffers-kill-emacs)’: Specifies the command to save all buffers and kill the Emacs server.

Example output: The running Emacs server will be stopped, and if any files have unsaved changes, a prompt will ask for confirmation before exiting.

Conclusion:

The ’emacsclient’ command is a versatile utility for interacting with an existing Emacs server. It provides a range of use cases such as opening files, evaluating commands, and managing instances. By understanding the different options and arguments, you can effectively utilize the power of Emacs through the command line.