Question

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

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）。我已经尝试过以下命令：

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

这不是我想要的，因为它代替了最后一行line two，而不是line one。

我想做什么：

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flatMap完成，例如：

tput

最初将打印：

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'

然后，在休眠0.5秒后line one - a long line # `tput sc` will point to this line line two <cursor> # cursor is left sitting on this line将导致光标在执行最后2x tput rc条命令之前向上移动2行：

printf

其他一些示例：here和here

一些文档：here和here

Answer 2

您可以通过打印特殊的转义序列在bash脚本中移动光标，请尝试以下代码：

#!/bin/bash

# print first line
printf "first line is long\n"
# print second line
printf "line 2\n"
sleep 1
# move cursor two steps UP
printf "\033[2A"
# print line 3 (without \n)
printf "line #3"
# clear rest of first line
# and move cursor two steps down
printf "\033[K\r\033[2B"

有关ANSI转义序列的更多信息：https://tldp.org/HOWTO/Bash-Prompt-HOWTO/c327.html

是否可以在不清除屏幕的情况下替换行？

2 个答案: