Go語言系統編程如何取得命令行參數或系統環境變量

     首先取得命令行參數:

用法如下：
	root@centos:~/code/go/self$ ./sum 1 2 4

	package main
	import "fmt"
	import "os"
	import "strconv"

	func main() int{
		arg_num := len(os.Args)
		fmt.Printf("the num of input is %d\n",arg_num)

		fmt.Printf("they are :\n")
		for i := 0 ; i < arg_num ;i++{
			fmt.Println(os.Args[i])
		}

		sum := 0
		for i := 1 ; i < arg_num; i++{
			curr,err := strconv.Atoi(os.Args[i])
			if(err != nil){
				fmt.Println("error happened ,exit")
				return 1
			}
			sum += curr
		}

		fmt.Printf("sum of Args is %d\n",sum)
		return 0
	}
	

獲取系統環境變量:

	package main
	import "fmt"
	import "os"

	func main(){
		environ := os.Environ()
		for i := range environ {
			fmt.Println(environ[i])
		}
		fmt.Println("------------------------------------------------------------\n")
		logname := os.Getenv("LOGNAME")
		fmt.Printf("logname is %s\n",logname)
	}