Copy and Paste with Xorg

There exist two buffers to perform copy and paste operations in Xorg: the
selection buffer and the clipboard buffer.

clipboard buffer

The clipboard buffer is the one people are the most used to. Generally to save
the selection into the clipboard buffer we simply press ctrl+c.
Note that in a terminal window the ctrl+c shortcut is going to terminate the
current application, therefore, we generally have to press ctrl+shift+c to
obtain the same result.

Similarly, to paste the clipboard content at the position of the cursor we have
to press ctrl+v or ctrl+shift+v in a terminal window.

selection buffer

The selection buffer contains the last text selected. Generally we paste the
selection buffer content by pressing the mouse middle button. We can also
perform the same action by pressing ctrl+insert or ctrl+shift+insert
depending on the application.

Note

Different graphical toolkits like gtk2, gtk3, Qt, etc can implement their own
clipboards which are not necessarily synchronized with the Xorg clipboard.