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C program to find file properties using stat() function

Stat() function in C is used to retrieve information about the file by accepting the filepath as an argument to it.

Stat() function can help us to extract following information about any file using C program.

  • File type and mode
  • Number of hard links from the file
  • User ID of file owner
  • Group ID of file owner
  • Device ID (if special file)
  • Total size, in bytes
  • Time of last access
  • Time of last modification
  • Time of last status change

Now, for our understanding here, we will create a simple text file (helloworld.txt) and check its information using the C program.

$ vim helloworld.txt
This is the text file containing some random text for stat demo.

Now, we will write the C program as below,

$ vim file_information.c
#include <sys/types.h>
#include <sys/stat.h>
#include <time.h>
#include <stdio.h>
#include <stdlib.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 (stat(argv[1], &sb) == -1) {
		perror("stat");
		exit(EXIT_FAILURE);
	}

	printf("File type:                ");

	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;
	}

	printf("I-node number:            %ld\n", (long) sb.st_ino);

	printf("Mode:                     %lo (octal)\n",
		(unsigned long) sb.st_mode);

	printf("Link count:               %ld\n", (long) sb.st_nlink);
	printf("Ownership:                UID=%ld   GID=%ld\n",
		(long) sb.st_uid, (long) sb.st_gid);

	printf("Preferred I/O block size: %ld bytes\n",
		(long) sb.st_blksize);
	printf("File size:                %lld bytes\n",
		(long long) sb.st_size);
	printf("Blocks allocated:         %lld\n",
		(long long) sb.st_blocks);

	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);
}

Compile the program on Linux terminal using GCC.

$ gcc -o file_information file_information.c
$ ./file_information helloworld.txt

So, the actual command would be “./file_information your_file_name.extention ”

This command now returns the information as below,

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