用c寫一個shell響應架子

#include <stdio.h>

#define cmd_exit "exit"
#define cmd_ll "ll"
#define cmd_cp "cp"
#define cmd_cat "cat"

int has(char * arr,char * cmd);
char * curl(char * url);
void cat(char * url);

int main()
{
	char arr[100];
	while(1)
	{
		printf("[root@localhost /]# ");
		gets(arr);	
		if(*(arr) == '\0')
		{
			continue;
		}


		if(has(arr,cmd_exit))
		{
			return 0;
		}
		if(has(arr,cmd_cp))
		{
			continue;
		}
		if(has(arr,cmd_ll))
		{
			printf("this is ll!\n");
			continue;
		}
		printf("cmd not found!\n");
	}
    return 0;
}

int has(char * arr,char * cmd){
	int i = 0;
	while(*(cmd + i) != '\0'){
		if(*(arr + i) != *(cmd + i)){
			return 0;
		}
		i++;
	}
	if(*(arr + i) != '\0'){
		return 0;
	}
	return 1;
}

char * cp(char * url){
	return NULL;
}