Variable `exec-path` Is Different Depending Upon How Emacs Is Launched.

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Introduction

When working with Emacs, it's essential to understand how the exec-path variable behaves depending on how the application is launched. In this article, we'll explore the differences in exec-path values when running Emacs from a desktop icon or launcher versus launching it from a shell. We'll also discuss possible solutions to achieve the desired behavior.

Understanding exec-path

exec-path is a variable in Emacs that stores the list of directories where Emacs searches for executable files. This variable is crucial for Emacs to find and execute external commands, such as those used in Lisp code or by packages. The value of exec-path can be customized, but it's often set by default based on the Emacs installation and the operating system.

Differences in exec-path values

When running Emacs from a desktop icon or launcher, the exec-path variable is set to:

("/usr/bin" "/bin" "/usr/sbin" "/sbin"
  "/Applications/Emacs.app/Contents/MacOS/libexec")

However, when launched from a shell (such as zsh), the exec-path value is:

("/Users/tfn/Software/ImageMagick/ImageMagick-7.1.1/build/bin"
  "/Users/tfn/.local/bin"
  "/usr/local/texlive/2022/bin/universal-darwin"
  "/opt/homebrew/opt/openjdk/bin" "/opt/homebrew/bin"
  "/opt/homebrew/sbin" "/usr/local/bin"
  "/System/Cryptexes/App/usr/bin" "/usr/bin" "/bin" "/usr/sbin"
  "/sbin"
  "/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/local/bin"
  "/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/bin"
  "/var/run/com.apple.security.cryptexd/codex.system/bootstrap/usr/appleinternal/bin"
  "/Applications/kitty.app/Contents/MacOS"
  "/Applications/Emacs.app/Contents/MacOS/libexec")

As you can see, the second value is the desired behavior, which includes the user's local bin directories and other system-wide directories.

Possible solutions

There are packages available that copy the value of the shell's $PATH into exec-path. However, if you're using a version of Emacs that doesn't have this feature, you can try the following solutions:

1. Use a package that sets exec-path to the shell's $PATH

You can install a package like exec-path-from-shell or exec-path-from-shell.el to set exec-path to the shell's $PATH. This package is available on MELPA and can be installed using the package manager.

2. Set exec-path manually in your Emacs configuration file

You can set exec-path manually in your Emacs configuration file (~/.emacs.d/init.el or ~/.emacs on some systems) using the following code:

(setenv "PATH" (concat (getenv "PATH") ":/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin"))

This code sets the PATH environment variable to include the system-wide directories.

3. Use a custom function to set exec-path

You can create a custom function to set exec-path based on the shell's $PATH. Here's an example function:

(defun set-exec-path-from-shell-path ()
  (let ((path (shell-command-to-string "$SHELL -l -c 'echo $PATH'")))
    (setenv "PATH" (concat (getenv "PATH") (substring path 0 (- (length path) 1)))))
  (setq exec-path (split-string (getenv "PATH") path-separator)))

This function sets exec-path to the shell's $PATH and splits the path into a list of directories.

Conclusion

In conclusion, the exec-path variable behaves differently depending on how Emacs is launched. By understanding the differences in exec-path values, you can choose the best solution to achieve the desired behavior. Whether you use a package, set exec-path manually, or create a custom function, you can ensure that Emacs has access to the necessary directories to execute external commands.

System Information

  • Operating System: macOS 15.3.1 (24D70)
  • Emacs Version: GNU Emacs 30.1 (build 1, aarch64-apple-darwin23.6.0, NS appkit-2487.70 Version 14.7.2 (Build 23H311))
  • Installation Method: Installed using Homebrew instructions
    Variable exec-path is different depending upon how Emacs is launched ===========================================================

Q: What is the exec-path variable in Emacs?

A: The exec-path variable in Emacs stores the list of directories where Emacs searches for executable files. This variable is crucial for Emacs to find and execute external commands, such as those used in Lisp code or by packages.

Q: Why is the exec-path value different when running Emacs from a desktop icon or launcher versus launching it from a shell?

A: The exec-path value is different because the desktop icon or launcher sets the exec-path variable to a default value, which includes the system-wide directories. However, when launched from a shell, the exec-path value is set to the shell's $PATH, which includes the user's local bin directories and other system-wide directories.

Q: How can I set the exec-path variable to the shell's $PATH?

A: You can set the exec-path variable to the shell's $PATH using a package like exec-path-from-shell or exec-path-from-shell.el. Alternatively, you can create a custom function to set exec-path based on the shell's $PATH.

Q: What are the benefits of setting the exec-path variable to the shell's $PATH?

A: Setting the exec-path variable to the shell's $PATH ensures that Emacs has access to the necessary directories to execute external commands. This can improve the overall performance and functionality of Emacs.

Q: Can I set the exec-path variable manually in my Emacs configuration file?

A: Yes, you can set the exec-path variable manually in your Emacs configuration file using the following code:

(setenv "PATH" (concat (getenv "PATH") ":/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin"))

This code sets the PATH environment variable to include the system-wide directories.

Q: What are some common issues that can occur when setting the exec-path variable?

A: Some common issues that can occur when setting the exec-path variable include:

  • Inconsistent exec-path values between different Emacs sessions
  • Failure to find executable files due to incorrect exec-path values
  • Conflicts between different exec-path values set by different packages or custom functions

Q: How can I troubleshoot issues related to the exec-path variable?

A: To troubleshoot issues related to the exec-path variable, you can try the following steps:

  • Check the value of the exec-path variable using the C-h v exec-path command
  • Verify that the exec-path value is consistent between different Emacs sessions
  • Check for conflicts between different exec-path values set by different packages or custom functions

Q: Can I customize the exec-path variable to include specific directories?

A: Yes, you can customize the exec-path variable to include specific directories using the exec-path function. For example:

(defun my-exec-path ()
  (append (split-string (getenv "PATH") path-separator)
          '("/usr/local/bin" "/usr/bin")))

This code sets the exec-path variable to include the system-wide directories and the /usr/local/bin and /usr/bin directories.

Conclusion

In conclusion, the exec-path variable is a crucial component of Emacs that determines the directories where Emacs searches for executable files. By understanding the differences in exec-path values and how to set the exec-path variable to the shell's $PATH, you can improve the overall performance and functionality of Emacs.