Quickstart¶

This page gives a quick introduction into Flycheck and an overview of its most important features. Before you start here please make sure that Flycheck is installed.

Enable Flycheck¶

Now add the following code to your init file to permanently enable syntax checking with Flycheck:

(add-hook 'after-init-hook #'global-flycheck-mode)

Install syntax checker programs¶

Now you need to install syntax checking programs for the languages you’d like to use Flycheck with. The list of supported languages tells you which languages Flycheck supports and what programs it uses.

For instance, you can install Pylint for Python and ESLint for Javascript:

$ pip install pylint
$ npm install eslint

Check syntax in a buffer¶

Now you are ready to use Flycheck in a Python or Javascript buffer. Visit a Python or Javascript file and check whether your Flycheck setup is complete with C-c ! v.

If everything is green, Flycheck will now start to check the buffer on the fly while you are editing. Whenever you make a mistake that eslint or Pylint can catch, Flycheck will highlight the corresponding place in the buffer with an error underline whose color reflects the severity of the issue. Additionally, Flycheck will put a symbol into the fringe for affected lines and show the total number of errors and warnings in the buffer in the mode line.

Navigate and list errors¶

With C-c ! n and C-c ! p you can now jump back and forth between erroneous places. If you keep on such a place for a little while Flycheck will show the corresponding error message in the each area. Likewise, if you hover such a place with the mouse cursor Flycheck will show the error message in a tooltip.

Press C-c ! l to pop up a list of all errors in the current buffer. This list automatically updates itself when you fix errors or introduce new ones, and follows the currently selected buffer. If the error list is selected you can type n and p to move up and down between errors and jump to their corresponding location in the buffer.