stat.c

#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/sysmacros.h>
#include <time.h>

int main(int argc, char *argv[])
{
    struct stat sb;

    if (argc != 2) {
        fprintf(stderr, "Usage: %s <pathname>\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    if (lstat(argv[1], &sb) == -1) {
        perror("lstat");
        exit(EXIT_FAILURE);
    }

    // unsigned int major(dev_t dev)
    // unsigned int minor(dev_t dev)
    printf("ID of containing device:  [%x,%x]\n",
           major(sb.st_dev),
           minor(sb.st_dev));

    printf("File type:                ");

    // S_IFMT : a bit mask used to extract the file type code from a mode value
    switch (sb.st_mode & S_IFMT) {
    case S_IFBLK:  printf("block device\n");            break;
    case S_IFCHR:  printf("character device\n");        break;
    case S_IFDIR:  printf("directory\n");               break;
    case S_IFIFO:  printf("FIFO/pipe\n");               break;
    case S_IFLNK:  printf("symlink\n");                 break;
    case S_IFREG:  printf("regular file\n");            break;
    case S_IFSOCK: printf("socket\n");                  break;
    default:       printf("unknown?\n");                break;
    }

    // uintmax_t: unsigned integer type with the maximum width supported.
    printf("I-node number:            %ju\n", (uintmax_t) sb.st_ino);
    printf("Mode:                     %jo (octal)\n", (uintmax_t) sb.st_mode);
    printf("Link count:               %ju\n", (uintmax_t) sb.st_nlink);
    printf("Ownership:                UID=%ju   GID=%ju\n", (uintmax_t) sb.st_uid, (uintmax_t) sb.st_gid);
    printf("Preferred I/O block size: %jd bytes\n", (intmax_t) sb.st_blksize);
    printf("File size:                %jd bytes\n", (intmax_t) sb.st_size);
    printf("Blocks allocated:         %jd\n", (intmax_t) sb.st_blocks);
    
    // char* ctime (const time_t * timer);
    // Convert time_t value to string
    printf("Last status change:       %s", ctime(&sb.st_ctime));
    printf("Last file access:         %s", ctime(&sb.st_atime));
    printf("Last file modification:   %s", ctime(&sb.st_mtime));

    exit(EXIT_SUCCESS);
}