/proc目录下是存放的是系统进程pid和服务名称。
[root@133 systeminformation]# ls /proc/
1 107 112 121 128 136 1498 158 17911 1961 24594 3 37 45 50 58 68 78 87 97 devices ipmi mdstat sched_debug timer_list
10 1075 113 1212 129 137 15 159 18 2 24641 30 38 4520 51 59 69 786 88 98 diskstats irq meminfo schedstat timer_stats
100 108 114 122 13 138 150 16 1882 20 24643 31 39 453 52 6 7 79 89 981 dma kallsyms misc scsi tty
101 10852 115 12252 130 139 151 160 19 2046 25 3164 4 454 527 60 70 8 9 99 driver kcore modules self uptime
102 10854 1154 123 13046 14 152 1621 190 21 25500 3188 40 456 528 61 71 80 90 acpi execdomains keys mounts slabinfo version
10275 109 116 12396 13047 140 1527 1622 191 21678 26 3190 409 46 53 62 72 81 91 buddyinfo fb key-users mpt softirqs vmallocinfo
10295 11 117 12398 131 141 153 1655 1951 21697 27 32 41 4665 54 63 73 82 92 bus filesystems kmsg mtd
＃定义一个函数，判断是否是数字
[root@133 systeminformation]# vim isNum.py
#!/usr/bin/env python
import sys
import os
import string
def isNum(s):
for i in s:
if i in string.digits:
continue
else:
return False
return True
for pid in os.listdir('/proc'):
if isNum(pid):
print pid
In [5]: import string
In [6]: string.digits #判断是否是数字
Out[6]: '0123456789'
[root@133 systeminformation]# python isNum.py ＃只打印数字，字母排除
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In [8]: for pid in os.listdir('/proc'): #使用pid.isdigit()判断是否是数字
...: if pid.isdigit():
...: print pid
...:
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