python写的树莓派实时监控温度，cpu使用率的小程序

linux中shell命令如下：

cat <(grep 'cpu ' /proc/stat) <(sleep 1 && grep 'cpu ' /proc/stat) | awk -v RS="" '{print ($13-$2+$15-$4)*100/($13-$2+$15-$4+$16-$5) "%"}'

此处其实为一个略简化计算方法，原理见

http://www.blogjava.net/fjzag/articles/317773.html

最终代码如下：

 #!/usr/bin/env python
 import os
 import time


 #show raspberry temperature,CPU,memory


 def getCPUtemp():
     temp = os.popen('vcgencmd measure_temp').readline()
     tempfloat = float(temp.replace('temp=','').replace('\'C\n',''))
     print 'CPU Temperature is now %.1f Centigrade' %tempfloat
     if tempfloat > 60:
         print 'CPU Temperature is too high, pls cool it down'


 def getCPUusage():
         #calculate CPU with two short time, time2 - time1
         time1 = os.popen('cat /proc/stat').readline().split()[1:5]
         time.sleep(0.2)
         time2 = os.popen('cat /proc/stat').readline().split()[1:5]
         deltaUsed = int(time2[0])-int(time1[0])+int(time2[2])-int(time1[2])
         deltaTotal = deltaUsed + int(time2[3])-int(time1[3])
         cpuUsage = float(deltaUsed)/float(deltaTotal)*100
     print 'CPU Usage is now %.1f' %cpuUsage +'%'


 def getRAM():
     #get RAM as list,list[7],[8],[9]:total,used,free
     RAM = os.popen('free').read().split()[7:10]
     #convert kb in Mb for readablility
     RAM0 = float(RAM[0])/1024
     print 'RAM Total is %.1f MB' %RAM0
     RAM1 = float(RAM[1])/1024
     percent = RAM1/RAM0*100
     print 'RAM Used  is %.1f MB, %.2f' %(RAM1,percent) +'%'
     RAM2 = float(RAM[2])/1024
     print 'RAM Free  is %.1f MB' %RAM2


 def getDisk():
     #get Disk information,DISK[8],[9],[10],[11]:Size, Used. free, Used %
     DISK = os.popen('df -h /').read().split()[8:12]
     print 'Disk total space is %s ' %DISK[0]
     print 'Disk Used  space is %s ' %DISK[1] +'and is %s' %DISK[3]
     print 'Disk Free  space is %s ' %DISK[2]




 while True:
     print '\n-------------SysInfo-----------------\n'
     getCPUtemp()
     getCPUusage()
     getRAM()
     getDisk()
     print '\n-------------------------------------\n'
     time.sleep(5)