Gnome

Screenshots

Modifier	Effect
ctrl	clipboard (otherwise PNG)
shift	select a region
alt	currently selected window

printscreen	save a png of the entire screen
shift + printscreen	select a region and save a png of it
ctrl + printscreen	print screen to clipboard
alt + printscreen	save a png of the currently selected window
shift + ctrl + printscreen	select a region and print it to the clipboard
ctrl + alt + printscreen	print the currently selected window to the clipboard

Settings

gsettings – GSettings configuration tool

gsettings list-schemas
gsettings list-keys org.gnome.desktop.default-applications.terminal
gsettings list-recursively org.cinnamon.desktop.default-applications
gsettings set org.cinnamon.desktop.default-applications.terminal exec xfce4-terminal

dconf-editor – Graphical editor for gsettings and dconf

GUI

GIO

GIO (Gnome Input/Output) is a library, designed to present programmers with a modern and usable interface to a virtual file system.

https://en.wikipedia.org/wiki/GIO_(software)

gio – GIO commandline tool

gio mime x-scheme-handler/http
gio mime x-scheme-handler/http exo-web-browser.desktop
gio mime x-scheme-handler/https exo-web-browser.desktop

File manager

Files (Nautilus)

Used to be Nautilus, now renamed to Files (although the name Nautilus still appears in most places and executables).

python3-nautilus

Let’s write python3 scripts for the file manager. The scripts are then saved in:

~/.local/share/nautilus-python/extensions

For instance to open an arbitrary Terminal:

# This example is contributed by Martin Enlund
import os

# A way to get unquote working with python 2 and 3
try:
    from urllib import unquote
except ImportError:
    from urllib.parse import unquote

import gi
gi.require_version('GConf', '2.0')
from gi.repository import Nautilus, GObject, GConf


class OpenTerminalExtension(Nautilus.MenuProvider, GObject.GObject):
    def __init__(self):
        self.client = GConf.Client.get_default()
        
    def _open_terminal(self, file):
        filename = unquote(file.get_uri()[7:])

        os.chdir(filename)
        #os.system('gnome-terminal')
        os.system('x-terminal-emulator')
        
    def menu_activate_cb(self, menu, file):
        self._open_terminal(file)
        
    def menu_background_activate_cb(self, menu, file): 
        self._open_terminal(file)
       
    def get_file_items(self, window, files):
        if len(files) != 1:
            return
        
        file = files[0]
        if not file.is_directory() or file.get_uri_scheme() != 'file':
            return
       
        item = Nautilus.MenuItem(name='NautilusPython::openterminal_file_item',
                                 label='Open Terminal' ,
                                 tip='Open Terminal In %s' % file.get_name())
        item.connect('activate', self.menu_activate_cb, file)
        return item,

    def get_background_items(self, window, file):
        item = Nautilus.MenuItem(name='NautilusPython::openterminal_file_item2',
                                 label='Open Terminal' ,
                                 tip='Open Terminal In %s' % file.get_name())
        item.connect('activate', self.menu_background_activate_cb, file)
        return item,