Here’s another simple bit of code that can be really handy as a hotkey or marking menu. All it does is copies the keys selected in the graph editor, and pastes them to the current frame. I use it all the time for grabbing a pose from an earlier frame, creating holds, and getting cycles to loop. It’s generally a quicker replacement for middle-mouse dragging the timeline to copy keys.
copyKey; pasteKey -option merge -t `currentTime -q` -copies 1 -connect 0;
Open up your graph editor, select some keys to copy, go to the frame you want to paste to, and then just run the command.