Code
vim
:reg " show all registers
"ayy " yank current line into register a
"ap " paste from register a
"+yy " yank line to system clipboard (+)
"*p " paste from system selection (*)
" " the unnamed register (last yank/delete)
0 " register 0: last yank
1-9 " numbered: last deletes (1 = most recent)
. " last inserted text
% " current file name
/ " last search pattern
" Clear a register: yank into it, or set to empty
:let @a = ""
" Append to a register with uppercase
"Ayy " append current line to register a