Linux C編程連載

Linux C編程連載——cp的實現：

1. /**********************************************************
2. * This program is use to copy src_file to dest_file
3. * 1 Execute gcc -o copy copy.c
4. * 2 then, copy the execute file "copy" to the /usr/bin
5. * You can use command like this : copy src_file dest_file
6. * Author : Tan De
7. * Time : 2011-04-04
8. *********************************************************/
10. #include <stdio.h>
11. #include <stdlib.h>
12. #include <unistd.h>
13. #include <sys/stat.h>
14. #include <sys/types.h>
15. #include <fcntl.h>
17. #define BUFF_SIZE 1024
19. int main(int argc, char *argv[]){
21. int src_file,dest_file;
22. int real_read_len;
23. unsigned char buff[BUFF_SIZE];
25. //argc is not correct
26. if(argc!=3){
27. printf("Error use copy!\n");
28. printf("Example:\n");
29. printf("copy src_file dest_file\n");
30. exit(1);
31. }
33. //Open src_file read only
34. src_file=open(argv[1],O_RDONLY);
35. //If the dest_file is not exsit, then create new one
36. dest_file=open(argv[2],O_WRONLY|O_CREAT,666);
37. //Open error
38. if(src_file<0||dest_file<0){
39. printf("Open file error\n");
40. printf("Can't copy!\n");
41. printf("Please check cmd : copy src_file dest_file\n");
42. exit(1);
43. }
45. //Copy src_file to dest_file
46. while((real_read_len=read(src_file,buff,sizeof(buff)))>0){
47. write(dest_file,buff,real_read_len);
48. }
50. //close fd
51. close(dest_file);
52. close(src_file);
54. return 0;
55. }