Linux下cat命令的实现

#include <stdio.h>
#include <string.h>
#include<unistd.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<fcntl.h>
int main(int argc,char* argv[])
{
    if(argc != 2){
        printf("Format should be:myCat filename/n");
    }
    int from_fd;
    char buf[255];
    from_fd = open("./argv[1]",O_RDONLY);
    while(1){
        int r = read(from_fd,buf,strlen(buf));
        write(1,buf,strlen(buf));
        if(r = 0){
            break;
        }
    }

    write(1,argv[1],strlen(argv[1]));
    printf("/n");
    return 0;
}