有没有办法在不清除屏幕的情况下替换行？

Question

printf "line one\n"
printf "line two\n"

在这些打印输出之后，我想替换第一行并打印其他内容（不使用clear）。我试过这样的命令：

printf "line one\n"
printf "line two\r"

这不是我想要的，因为它替换了最后一行line two，而不是line one.

我想做的事：

printf "line one\n"
printf "line two\n"
sleep 0.5
somecode "line three"

我想要的输出：

line three
line two

Answer 1

这可以通过tput，例如：

EraseToEOL=$(tput el)                 # save control code for 'erase to end of line'
tput sc                               # save pointer to current terminal line

printf "line one - a long line\n"
printf "line two\n"
sleep 0.5

tput rc                               # return cursor to last cursor savepoint (`tput sc`)
printf "line three${EraseToEOL}\n"    # print over `line one - a long line`; print `$EraseToEOL` to clear rest of line (in case previous line was longer than `line three`)
printf "\n"                           # skip over 'line two'

这将最初打印：

line one - a long line                # `tput sc` will point to this line
line two
<cursor>                              # cursor is left sitting on this line

然后在休眠 0.5 秒tput rc后将导致光标在执行最后 2x 个printf命令之前“向上”移动 2 行：

line three                            # old 'line one - a long line` is overwritten
line two                              # `printf "\n"` won't print anything new on this line so the old contents won't be overwritten, while the cursor will be moved to the next line
<cursor>                              # cursor is left sitting on this line

其他一些例子：这里和这里

一些文档：这里和这里