bash 如何从 php cli 回显退格？
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How do I echo a backspace from php cli?
提问by Benubird
This question: https://askubuntu.com/questions/16149/overwrite-previous-output-in-bash-instead-of-appending-it
这个问题：https: //askubuntu.com/questions/16149/overwrite-previous-output-in-bash-instead-of-appending-it
Explains how to do a countdown as a bash script. I want to do the same thing, but I need to do it in PHP. Is there a way to echo a backspace?
解释如何以 bash 脚本的形式进行倒计时。我想做同样的事情，但我需要用 PHP 来做。有没有办法回显退格？
e.g.
例如
echo "Counting down 60\n";
sleep(1);
echo "\b\b\b59\n";
sleep(1);
echo "\b\b\b58\n";
But, echo "\b" doesn't do anything.
但是， echo "\b" 不做任何事情。
回答by Olaf Dietsche
From Strings - Double quoted, there is no \brecognized as an escape sequence. You can use the ASCIIbackspace hex or octal code
从字符串 - 双引号，没有被\b识别为转义序列。您可以使用ASCII退格十六进制或八进制代码
$bs = "\x08";
echo "Counting down 60";
sleep(1);
echo "$bs$bs59";
sleep(1);
echo "$bs$bs58";
or in a loop all the way down to zero
或一直循环到零
$bs = "\x08";
for ($i = 59; $i >= 0; --$i) {
sleep(1);
printf("$bs$bs%2d", $i);
}
You must omit the newline \nas well.
您还必须省略换行符\n。
