I use MATE as desktop viewer. How can I add a shortcut for taking a screenshot of a part of the windows and copy it to the clipboard? Basically what with gnome the command control-shift-stamp.
For Gnome, copying portion of the screen to clipboard is Ctrl+Shift+PrtScrn.
It looks like they've recently removed this in the newest versions on GNOME, but you can reinstate it by combining some of the existing answers here, specifically:
Go to Settings > Keyboard > View and Customize Shortcuts > Custom Shortcuts.
Click the + and create a new shortcut with:
gnome-screenshot -acf /tmp/gnome-screenshot-area
Shortcut Shift + Ctrl + Print
Note: saving the screenshot to file is intentional (thanks @grabantot).
Another note: I switched back to Wayland, which seems to have broken this method.