反向索引 (RI)

该序列不会取消待处理的换行状态。

如果光标恰好位于 上边距，且处于 左右边距 之内，则以 n = 1 调用 向下滚动 (SD)。操作结束。

否则无需滚动。以 n = 1 执行 光标上移 操作。

printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "A\n"
printf "B\n"
printf "C\n"
printf "\033[1;1H" # move to top-left
printf "\033M" # reverse index
printf "X"

|Xc________|
|A_________|
|B_________|
|C_________|

printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "A\n"
printf "B\n"
printf "C\n"
printf "\033[2;1H"
printf "\033M" # reverse index
printf "X"

|Xc________|
|B_________|
|C_________|

printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "A\n"
printf "B\n"
printf "C\n"
printf "\033[2;3r" # scroll region
printf "\033[2;1H"
printf "\033M" # reverse index

|A_________|
|c_________|
|B_________|

printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "A\n"
printf "B\n"
printf "C\n"
printf "\033[2;3r" # scroll region
printf "\033[1;1H"
printf "\033M" # reverse index

|A_________|
|B_________|
|C_________|

printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "ABC\n"
printf "DEF\n"
printf "GHI\n"
printf "\033[?69h" # enable left/right margins
printf "\033[2;3s" # scroll region left/right
printf "\033[1;2H"
printf "\033M"

|A_________|
|DBC_______|
|GEF_______|
|_HI_______|

printf "\033[1;1H" # move to top-left
printf "\033[0J" # clear screen
printf "ABC\n"
printf "DEF\n"
printf "GHI\n"
printf "\033[?69h" # enable left/right margins
printf "\033[2;3s" # scroll region left/right
printf "\033[2;1H"
printf "\033M"

|ABC_______|
|DEF_______|
|GHI_______|

光标位于 A 上。