How to read file/folder properties in Linux?

Question

How to retrieve a file/folder's properties in C, particularly in Linux?

I need info about date created, last modified, isDirectory or isFile, permission, ownership and size.

Thanks.

possible duplicate of [How to get file information similar to "ls -la" using C?](http://stackoverflow.com/questions/7943220/how-to-get-file-information-similar-to-ls-la-using-c) — Ignacio Vazquez-Abrams, Aug 01 '12 at 18:58
good documentation here, I would hate to see this closed as a duplicate.. — Karoly Horvath, Aug 01 '12 at 19:13
@Karoly: What documentation? Everything below is in the man page. — Ignacio Vazquez-Abrams, Aug 01 '12 at 19:15

score 4 · Accepted Answer · 2012-08-01T22:34:36.263

4

You most likely need the stat() function.

Example:

struct stat attr;
stat("/home/crazyfffan/foo.txt", &attr);

printf("Size: %u\n", (unsigned)attr.st_size);
printf("Permissions: %o\n", (int)attr.st_mode & 07777);
printf("Is directory? %d\n", attr.st_mode & ST_ISDIR);

etc.

edited Aug 01 '12 at 22:34

answered Aug 01 '12 at 18:57

The last line does not compile, instead I use: `printf("Is directory? %d\n", S_ISDIR(attr.st_mode));` – Max Aug 01 '12 at 22:11

pb2q · Answer 2 · 2012-08-01T22:56:37.347

Use the stat system call. man 2 stat.

You'll get a structure that includes what you're looking for.

From the man page:

struct stat {
           dev_t     st_dev;     /* ID of device containing file */
           ino_t     st_ino;     /* inode number */
           mode_t    st_mode;    /* protection */
           nlink_t   st_nlink;   /* number of hard links */
           uid_t     st_uid;     /* user ID of owner */
           gid_t     st_gid;     /* group ID of owner */
           dev_t     st_rdev;    /* device ID (if special file) */
           off_t     st_size;    /* total size, in bytes */
           blksize_t st_blksize; /* blocksize for file system I/O */
           blkcnt_t  st_blocks;  /* number of 512B blocks allocated */
           time_t    st_atime;   /* time of last access */
           time_t    st_mtime;   /* time of last modification */
           time_t    st_ctime;   /* time of last status change */
       };

Look over the example in the man page for details about determining file type using the st_mode field; here's how to check isDirectory/isFile using the POSIX macros:

isDirectory = S_ISDIR(statBuf.st_mode);
isFile = S_ISREG(statBuf.st_mode);

score 1 · Answer 3 · answered Aug 01 '12 at 19:05

struct stat file_stats;    

fd = open(filename, O_RDONLY);
if (fd == -1) {
    exit(-1);
}

if (fstat(fd, &file_stats) < 0) {
    exit(-1);
}
if (S_ISDIR(file_stats.st_mode)) {
      printf("It is dir\n");
} else {
    snprintf(msg, PATH_MAX, "%lld, %ld, %o, %d, %d, %d, %lld, %ld, %ld, %ld, %ld, %ld,
    %ld\n",
            file_stats.st_dev,
            file_stats.st_ino,
            file_stats.st_mode,
            file_stats.st_nlink,
            file_stats.st_uid,
            file_stats.st_gid,
            file_stats.st_rdev,
            file_stats.st_size,
            file_stats.st_blksize,
            file_stats.st_blocks,
            file_stats.st_atime,
            file_stats.st_mtime,
            file_stats.st_ctime);
}

without some description of what the fields are for, this is not as helpful as it could be. — , Aug 01 '12 at 19:10

How to read file/folder properties in Linux?

3 Answers3