前言:
在给nagios开发监控插件的时候,不论是用哪种语言写插件,最好能从命令行获得参数(警告值和报警值:-w warning_value -c critical_value),而不是在插件里把这两个值写进去,通常情况下会随着环境改变而更改警告和报警值。
官方文档:sys.argvThe list of command line arguments passed to a Python script. argv[0] is the script name (it is operating system dependent whether this is a full pathname or not). If the command was executed using the -c command line option to the interpreter, argv[0] is set to the string '-c'. If no script name was passed to the Python interpreter, argv[0] is the empty string.
sys.argv命令列表,第一个元素argv[0]是脚本名,argv[1]表示第1个参数,argv[2]表示第2个参数,以此类推。
举个简单的例子:
#!/usr/bin/env pythonimport sysdef PrintArgv(): # 如果需要list中的index,可以用内置的enumerate函数实现; print('all para(s):', sys.argv) print('script name:', sys.argv[0]) if sys.argv[1:]: index = 1 for para in sys.argv[1:]: print('para', index, ':', para) index += 1
import sys
def PrintArgv():
print('all para(s):', sys.argv)
print('script name:', sys.argv[0])
argv_list = list(enumerate(sys.argv))
if sys.argv[1:]:
for para in argv_list[1:]:
print('para', para[0], ':', para[1])
PrintArgv()
>python test.pyall para(s): ['test.py']script name: test.py>python test.py 'name' 913all para(s): ['test.py', "'name'", '913']script name: test.pypara 1 : 'name'para 2 : 913>python test.py 'name' 913 [1,2]all para(s): ['test.py', "'name'", '913', '[1,2]']script name: test.pypara 1 : 'name'para 2 : 913para 3 : [1,2]
可以看出,参数默认为字符串类型,同input一样,需要转换为int类型的传入参数时需要注意。
shell实现:$变量
shell脚本中可以通过变量的方式调用命令传入的参数,$0为脚本名,第一个参数$1,第二个参数$2,以此类推。特别的,$#表示参数个数,$@表示所有参数。
简单例子:
# --para.sh--
#!/bin/bashecho "all para(s): " $@echo "script name: " $0for index in `seq 1 $#`do echo "para ${index}: " $1 shiftdone
[root@oam shell]# ./para.shall para(s):script name: para.sh[root@oam shell]# ./para.sh hello lei 2014all para(s): hello lei 2014script name: para.shpara 1: hellopara 2: leipara 3: 2014
C/C++实现
C和C++都允许从命令行给main函数传入参数:int main(int argc, char*argv[]),argc表示有几个参数将传给main函数,参数以字符串数组argv[]的形式传递。同样argv[0]表示二进制文件名,argv[1]表示第一个参数,argv[2]表示第二个参数,依此类推。
简单的例子:
#include<iostream>using namespace std;int main(int argc, char *argv[]){ cout << "file name: " << argv[0] << endl; cout << "para num: " << argc << endl; for (int i=1; i<argc; i++) { cout << "para " << i << ": " << argv[i] << endl; } return 0;}
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