日期：2019/3/16
作业：实现命令cat, cp, echo。
myecho命令
#include <stdio.h> int main(int argc, char *argv[]) { int i = 0; printf("argument count = %d\n", argc); for (; i < argc; i++) printf("%s\n", argv[i]);
扫描二维码关注公众号，回复：
5622578 查看本文章
return 0; } |
mycat命令
#include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/stat.h> #include <fcntl.h> static char buf[256] = {0}; int main(int argc, char *argv[]) { printf("Running program is %s\n", argv[0]); printf("Argument count is %d\n", argc); printf("File name is %s\n", argv[1]); int file_desc = open(argv[1], O_RDONLY); if (file_desc == -1) { perror("file is not existed!"); exit(EXIT_FAILURE); } int flag = read(file_desc, buf, 255); while (flag != 0 && flag != -1) { printf("%s", buf); memset(buf, 0, sizeof(buf)); flag = read(file_desc, buf, 255); } return 0; }
|
mycp命令
不支持dst为目录的cp命令。
#include <stdio.h> #include <stdlib.h> #include <sys/stat.h> #include <fcntl.h> #include <unistd.h> static char buf[256] = {0}; int main(int argc, char *argv[]) { printf("src is %s\n", argv[1]); printf("dst is %s\n", argv[2]); int src = open(argv[1], O_RDONLY); if (src == -1) { perror("file doesn't exist!\n"); exit(EXIT_FAILURE); } int dst = open(argv[2], O_RDWR | O_CREAT); int flag = read(src, buf, 255); while (flag != 0 && flag != -1) { write(dst, buf, 255); memset(buf, 0, sizeof(buf)); flag = read(src, buf, 255); } return 0; }
|
mycp2命令
支持dst为目录。
#include <sys/types.h> #include <dirent.h> #include <string.h> #include <stdio.h> #include <stdlib.h> #include <sys/stat.h> #include <fcntl.h> #include <unistd.h> static char buf[256] = {0}; void cp_to_file(int src, int dst) { int flag = read(src, buf, 255); while (flag != 0 && flag != -1) { write(dst, buf, flag); memset(buf, 0, sizeof(buf)); flag = read(src, buf, 255); } close(src); close(dst); } int main(int argc, char *argv[]) { printf("src is %s\n", argv[1]); printf("dst is %s\n", argv[2]); int src = open(argv[1], O_RDONLY); if (src == -1) { perror("file doesn't exist!\n"); exit(EXIT_FAILURE); } int dst; DIR *pdir = opendir(argv[2]); if (pdir == NULL) { //dst is file dst = open(argv[2], O_RDWR | O_CREAT); cp_to_file(src, dst); } else { //dst is dir printf("%s is a dir\n", argv[2]); char temp[256]; strcpy(temp, argv[2]); if (temp[strlen(temp) - 1] != '/') strcat(temp, "/"); strcat(temp, argv[1]); puts(temp); dst = open(temp, O_RDWR | O_CREAT); cp_to_file(src, dst); } return 0; }
|