以毫秒为单位的 Bash 睡眠

Bash sleep in milliseconds

提问by Noqrax

I need a timer which will work with milliseconds. I tried to use sleep 0.1command in a script, but I see this error message:

我需要一个以毫秒为单位的计时器。我尝试sleep 0.1在脚本中使用命令，但看到以下错误消息：

syntax error: invalid arithmetic operator (error token is ".1")

syntax error: invalid arithmetic operator (error token is ".1")

When I run sleep 0.1in terminal it works fine.

当我sleep 0.1在终端中运行时，它工作正常。

Please help me!

请帮我！

EDIT: Sorry I have made a mistake:

编辑：对不起，我犯了一个错误：

function timer
{
while [[ 0 -ne $SECS ]]; do
    echo "$SECS.."
    sleep 0.1
    SECS=$[$SECS-0.1]
done
}

Line sleep 0.1was 5th and SECS=$[$SECS-0.1]was 6th. I just garbled lines. The problem was in 6th line, because bash can't work with float numbers. I changed my function as below:

行sleep 0.1是第 5 行和SECS=$[$SECS-0.1]第 6 行。我只是乱码。问题出在第 6 行，因为 bash 不能处理浮点数。我改变了我的功能如下：

MS=1000
function timer
{
while [[ 0 -ne $MS ]]; do
    echo "$SECS.."
    sleep 0.1
    MS=$[$MS-100]
done
}

回答by kenorb

Make sure you're running your script in Bash, not /bin/sh. For example:

确保您在 Bash 中运行脚本，而不是/bin/sh. 例如：

#!/usr/bin/env bash
sleep 0.1

In other words, try to specify the shell explicitly. Then run either by: ./foo.shor bash foo.sh.

换句话说，尝试明确指定 shell。然后通过以下方式运行：./foo.sh或bash foo.sh。

In case, sleepis an alias or a function, try replacing sleepwith \sleep.

如果sleep是别名或函数，请尝试替换sleep为\sleep。

回答by Jose H. Rosa

Some options:

一些选项：

read -p "Pause Time .5 seconds" -t 0.5

or

或者

read -p "Continuing in 0.5 Seconds...." -t 0.5
echo "Continuing ...."

回答by Evhz

Bash was complaining about decimal values,

Bash 抱怨十进制值，

read: 0.5: invalid timeout specification

读取：0.5：无效的超时规范

I came around with thissolution which works great.

我想到了这个效果很好的解决方案。

sleep_fraction() {
  /usr/bin/perl -e "select(undef, undef, undef, )"
}

sleep_fraction 0.01428