Output of stat on OSX – Portability Guide

There are two parts in deciphering what the "raw mode in hex" means; the first is that it's in hex, but access modes are generally described in octal:

41ed16 = 407758
81a416 = 1006448

If you were to look at /tmp, which typically has the restricted deletion flag ('sticky bit') set:

$ ls -ld /tmp
drwxrwxrwt 17 root root 4096 2012-05-31 13:45 /tmp
$ stat --format '%f %a' /tmp
43ff 1777

and converting:

43ff16 = 417778

The "raw mode in hex" is described in the programmer's manual for the stat function (man 2 stat), noting that they are octal values:

The following flags are defined for the st_mode field:

S_IFMT     0170000   bit mask for the file type bit fields
S_IFSOCK   0140000   socket
S_IFLNK    0120000   symbolic link
S_IFREG    0100000   regular file
S_IFBLK    0060000   block device
S_IFDIR    0040000   directory
S_IFCHR    0020000   character device
S_IFIFO    0010000   FIFO
S_ISUID    0004000   set UID bit
S_ISGID    0002000   set-group-ID bit (see below)
S_ISVTX    0001000   sticky bit (see below)
S_IRWXU    00700     mask for file owner permissions
S_IRUSR    00400     owner has read permission
S_IWUSR    00200     owner has write permission
S_IXUSR    00100     owner has execute permission
S_IRWXG    00070     mask for group permissions
S_IRGRP    00040     group has read permission
S_IWGRP    00020     group has write permission
S_IXGRP    00010     group has execute permission
S_IRWXO    00007     mask for permissions for others (not in group)
S_IROTH    00004     others have read permission
S_IWOTH    00002     others have write permission
S_IXOTH    00001     others have execute permission

(Strangely, the online man page is missing this section.)

This is a bit field, and we can see that the last four digits match the access mode; the leading digit (in hex) matches the file type, so a hex mode of 81a4 corresponds to "directory, mode 0644", and a hex mode of 41ed corresponds to "regular file, mode 0775".

Unix, and by inheritance, Linux and *BSD, get the "file status" via one of the stat-related systems calls: stat(), fstat() and lstat(). I believe the original was stat(). The "status" in this case constitutes what we currently call metadata: information about the file, like ownership, permissions, sizes, access, modification and status change times, things like that.

Whoever wrote the error message you quote ("unable to stat") used the name of the Unix/Linux/*BSD system call as a verb. That would be consistent with a lot of the system calls, which have names like "read", "write", "close", "open". In the context of using and thinking about Unix system calls, using "stat" as a verb comes pretty naturally.

So, "to stat" a file, is to get some or all of the file's metadata.