C language getopt and go language flag get command parameters

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The getopt () function in the C language provides a great convenience for command parameter acquisition, similar to the flag function in Golang.

C Language Getopt

     下面以ssh中获取主机名/ip和用户名为例来示例如何使用getopt().

    int get_user_host (int ac, char **av, Char *host, char *user) {char *p, *CP;    extern int optind;    int opt; Again:while (opt = getopt (AC, AV, "1246aacfgkkmnnqsttvvxxyyb:c:d:e:f:i:i:l:l:m:o:o:p:r:s:w:w:")))!! =-1) {SWITC        H (opt) {case ' 1 ': break;        Case ' 2 ': break;        Case ' 4 ': break;        Case ' 6 ': break;        Case ' A ': break;        Case ' a ': break;        Case ' C ': break;        Case ' F ': break;        Case ' G ': break;        Case ' K ': break;        Case ' K ': break;        Case ' M ': break;        Case ' N ': break;        Case ' n ': break;        Case ' Q ': break;        Case ' s ': break;        Case ' T ': break;        Case ' t ': break;        Case ' V ': break;        Case ' V ': break;        Case ' X ': break; Case ' X': break;        Case ' Y ': break;        Case ' Y ': break;        Case ' B ': break;        Case ' C ': break;        Case ' D ': break;        Case ' E ': break;        Case ' F ': break;        Case ' I ': break;        Case ' I ': break;        Case ' L ': break;        Case ' l ': break;        Case ' m ': break;        Case ' O ': break;        Case ' o ': break;        Case ' P ': break;        Case ' R ': break;        Case ' S ': break;        Case ' W ': break;        Case ' W ': break;        default:return-3;    }} ac-= Optind;    AV + = optind; if (ac > 0 && strlen (host) ==0 && **av! = '-') {if (STRRCHR (*av, ' @ ')) {p = strdup (            *AV);            cp = STRCHR (P, ' @ '); if (cp = = NULL | | cp = = p) {printf ("can Not find username nearby @ ");                printf ("\ n");            return-1;;            } *CP = ' + ';            user = strcpy (user, p);        Host = strcpy (HOST,++CP);        } else{host = strcpy (host, *AV);          } if (AC >1) {optind = 1;       Goto again;     } ac--, av++;        } if (strlen (host) ==0) {printf ("Can not find the host address in Parameters");        printf ("\ n");    Return-2; }return 0;}

Go language Flag

    go的flag相比于c的getopt使用起来简单很多。

cfgPath := flag.String("c","/etc/cfg.toml","cfg path")nowaitFlag :=flag.Bool("w",false,"do not wait")

The first command in the function is the indicator in "-C", "-w", the second is the default value, and the third is the description. No matter the order, as long as the normal appearance can be resolved.