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问题[rc](unix)

Martin Hope
z.h.
Asked: 2018-05-07 17:24:21 +0800 CST
  • 1

我将一个带有无限循环的python脚本放入/etc/rc.local但机器成功启动，这让我感到困惑。

内容/etc/rc.local：

#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

# Print the IP address
_IP=$(hostname -I) || true
if [ "$_IP" ]; then
  printf "My IP address is %s\n" "$_IP"
fi

/home/pi/py/startsignal.py &
/home/pi/py/fan.py
touch /home/pi/thisisrun
exit 0

启动信号.py

#!/usr/bin/python
import RPi.GPIO as GPIO

GPIO.setmode(GPIO.BCM)
GPIO.setup(18, GPIO.OUT)

GPIO.output(18, 1)

风扇.py

#!/usr/bin/python
# coding: utf8
import RPi.GPIO as gpio

gpio.setmode(gpio.BCM)
upper_temp = 55
lower_temp = 45
# minutes
check_interval = 2

def get_temp():
    with open('/sys/class/thermal/thermal_zone0/temp', 'r') as f:
        temp = float(f.read()) / 1000
    return temp

def check_temp():
    if get_temp() > upper_temp:
        gpio.setup(23, gpio.OUT)
    elif get_temp() < lower_temp:
        gpio.setup(23, gpio.IN)

if __name__ == '__main__':
    # check every 2 minutes
    try:
        while True:
            check_temp()
            sleep(check_interval * 60)
    finally:
        gpio.cleanup()

所有相关的代码都在上面。谷歌搜索后我想到了这个。

  1. 表示#!/bin/sh -e一旦发生错误脚本将退出。
  2. 文件没有创建，所以这/home/pi/thisisrun行上面一定有错误
  3. 启动到系统后，我可以看到它fan.py正在运行。所以我猜错误发生在fan.py. 但是fan.py里面有一个无限循环！

python脚本如何产生错误但仍然正常运行？

当永远不会返回时如何/bin/sh检测错误？fan.py

操作系统：树莓派拉伸

shell rc