Suppose you select text with the keyboard- in JOE you can do this by holding down Ctrl and repeatedly hit arrow keys (actually there are many ways to this- ^KB

Suppose you select text with the keyboard- in JOE you can do this by holding down Ctrl and repeatedly hit arrow keys (actually there are many ways to this- ^KB ^KK marking is another). In most editors for Windows you can do it by holding Shift and hit arrow keys. How is X supposed to know that you just made this selection? Normally it can not, because it's a tty/console application not in direct communication with the X server. The base64 selection feature allows a console application to do it: the program can send selection text to X any time it wants: it's some header, base64 text, and a trailer. When the terminal emulator receives this, it forwards it to the X server just as if you had done a mouse selection. The base64 is useful in the other direction (pasting into the terminal emulator running an editor). One minor advantage is that base64 is binary clean. Another is that the text is not just sent to the application- instead you get a sequence indicating that middle mouse button was pressed. The application then sends a request to the terminal emulator to have it send the paste data to the application. This is better because it allows you to paste by (for example) using an application specific keyboard sequence, not just a mouse action.