Sublime Text 3 save listener to auto run pyflakes (lint) python files.

PyflakesSaveListener.py

import re
import sublime
import sublime_plugin
import webbrowser


REG_RENAME = re.compile("\.(py)$")
EXT = re.compile(".*\.(py)$")
COMMAND = "pyflakes3 "


def is_python_file(file_name):
    return EXT.match(file_name) is not None


class PyflakesSaveListener(sublime_plugin.EventListener):
    def on_post_save(self, view):
        file_name = view.file_name()
        if is_python_file(file_name):
            sublime.status_message("pyflakes3 linting... " + file_name)
            self.run_shell_command(view, COMMAND + " " + file_name)

    def run_shell_command(self, view, command):
        if not command:
            return False
        view.window().run_command("exec", {
            "cmd": [command],
            "shell": True,
            "quiet": True
        })
        return True