Question

我目前正在创建一个带有显示屏的Raspberry Pi（Model B）温度传感器。我试图在LX终端中运行一个shell启动脚本，但是在Python子脚本旁边继续出现“Permission Denied”错误，如下所示：

pi@raspberrypi ~ $ sudo /home/pi/tempsense/etc/init.d/envmon start
Starting envmon
pi@raspberrypi ~ $ /home/pi/tempsense/etc/init.d/envmon: 15:/home/pi/tempsense/etc/init.d/envmon: home/pi/tempsense/opt/envmon/displayenvmon.py: Permission denied

shell脚本是：

#!/bin/sh
### BEGIN INIT INFO
# Provides:          envmon
# Required-Start:    $local_fs
# Required-Stop:     $local_fs
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Start/stop envmon
### END INIT INFO

case "$1" in
  start)
    /home/pi/tempsense/opt/envmon/dht11 &
    echo "Starting envmon"
    /home/pi/tempsense/opt/envmon/displayenvmon.py &
    ;;
  stop)
    pkill dht11
    pkill displayenvmon
    echo "envmon stopped"
    ;;
  *)
    echo "Usage: /home/pi/tempsense/etc/init.d/envmon {start|stop}"
    exit 1
    ;;
esac
exit 0

导致Permission denied错误的Python脚本是：

#!/usr/local/lib/python2.7/dist-packages
from RPLCD import CharLCD
import RPi.GPIO as GPIO
import subprocess, re
import time

# Data file - current reading
datfile = "/var/envmon.data"

# Rate at which the LCD is updated
UPDATE_RATE = 5


lcd = CharLCD(cols=16, rows=2, 
        pin_rw=None,
        pin_rs=7,
        pin_e=8,
        pins_data=[25,24,23,18],
        numbering_mode=GPIO.BCM)


lcd.cursor_pos = (0, 0)
lcd.write_string('Visit @UWS_Pi')
lcd.cursor_pos = (1, 0)
lcd.write_string('TEMP & HUMID')
time.sleep(5);


# Get IP address - looks for first IP address which is not 127.0.0.1
address_string = subprocess.getoutput("ip addr")
ipaddr = "Unknown"

# Reg exp to extract IP addresss
search_inet = re.compile('inet (\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})')  

for line in address_string.split('\n') :

    match = search_inet.search(line)
    if (match != None) :

        if (match.group(1) != '127.0.0.1') : 
            ipaddr = match.group(1)
            break

# Print the IP address to the LCD
lcd.cursor_pos = (1,0)
lcd.write_string (ipaddr)

# Sleep to give chance to read IP address   
time.sleep(5) 

# Loop get most recent reading and display on screen
while (True):

    fh = open (datfile, "r")
    entry = fh.read()

    # split into separate entries
    [currtime, currtemp, currhumid] = entry.split()

    # Change currtime to a formatted time ready for displaying
    formattime = time.strftime ("%d/%m/%Y %H:%M", time.localtime(int(currtime)))
    # print time to display
    lcd.cursor_pos = (0,0)
    lcd.write_string (formattime)

    # Print temp and humidity values
    lcd.cursor_pos = (1,0)
    lcd.write_string ("T " + currtemp + "C  RH " + currhumid + "%   ") 

    time.sleep(UPDATE_RATE)

我是新手，我们非常感谢任何有用的建议。

Answer 1

要使用GPIO引脚，需要使用管理员权限运行Python脚本。以root身份执行shell脚本或使用shell脚本中的sudo调用Python脚本。

尝试运行Shell脚本（包含Python子脚本）时拒绝权限

1 个答案: