10.25 刷新标准输入的缓冲区

[vieyahn2017]

刷新标准输入的缓冲区

[vieyahn2017]

比如这样的测试脚本

sleep 10
echo "read eee"
read -s eee

echo "===${ee

在sleep 10阶段，在键盘上随便按键，其输入内容会被缓冲区记录，
后续执行read的时候，读入的变量跟预期的不符，是之前按键输入的。
这就是缓冲区没清空导致的

[vieyahn2017]

输入脚本如何刷新输入缓冲区 https://segmentfault.com/q/1010000000260137

[vieyahn2017]

#!/bin/bash

#刷新标准输入的函数
function flush() {
local RET=0
while [ $RET -eq 0 ]
do
read -t 1
RET=$?
done
}

function menu() {
flush
echo "please input your choice:(a or o)?"
read input
case $input in
a|o)
echo "your choice is " $input
;;
*)
echo "invalid input! please input again!"
menu
;;
esac
}

echo "sleep 10s ..."
sleep 10    #这段睡眠时间里如果有输入，也不会被下面的menu函数接收到，因为flush函数会把它们先读走
menu

[vieyahn2017]

我改造的：

##刷新标准输入的缓冲区
function flush_before_read() {
    local RET=0
    while [ $RET -eq 0 ]
        do
            read -t 1
            RET=$?
        done
}

func_read_yes_no () {
    flush_before_read
    retry_times=1
    while [ $retry_times -le 3 ]; do
        read yesno
        if [[ "$yesno" == "yes" ]] || [[ "$yesno" == "y" ]];then
            echo $1
            return
        elif [[ "$yesno" == "no" ]] || [[ "$yesno" == "n" ]];then
            echo "you choose no, now will exit install."
            exit 0
        else
            echo "Invalid input, (yes/no) expected. Please re-enter."
            retry_times=`expr $retry_times + 1`
        fi
    done
    echo "Invalid input for more than 3 times, exit now."
    exit 1
}