Perl 5 version 32.0 documentation

stat

  • stat FILEHANDLE

  • stat EXPR
  • stat DIRHANDLE
  • stat

    Returns a 13-element list giving the status info for a file, either the file opened via FILEHANDLE or DIRHANDLE, or named by EXPR. If EXPR is omitted, it stats $_ (not _ !). Returns the empty list if stat fails. Typically used as follows:

    1. my ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,
    2. $atime,$mtime,$ctime,$blksize,$blocks)
    3. = stat($filename);

    Not all fields are supported on all filesystem types. Here are the meanings of the fields:

    1. 0 dev device number of filesystem
    2. 1 ino inode number
    3. 2 mode file mode (type and permissions)
    4. 3 nlink number of (hard) links to the file
    5. 4 uid numeric user ID of file's owner
    6. 5 gid numeric group ID of file's owner
    7. 6 rdev the device identifier (special files only)
    8. 7 size total size of file, in bytes
    9. 8 atime last access time in seconds since the epoch
    10. 9 mtime last modify time in seconds since the epoch
    11. 10 ctime inode change time in seconds since the epoch (*)
    12. 11 blksize preferred I/O size in bytes for interacting with the
    13. file (may vary from file to file)
    14. 12 blocks actual number of system-specific blocks allocated
    15. on disk (often, but not always, 512 bytes each)

    (The epoch was at 00:00 January 1, 1970 GMT.)

    (*) Not all fields are supported on all filesystem types. Notably, the ctime field is non-portable. In particular, you cannot expect it to be a "creation time"; see Files and Filesystems in perlport for details.

    If stat is passed the special filehandle consisting of an underline, no stat is done, but the current contents of the stat structure from the last stat, lstat, or filetest are returned. Example:

    1. if (-x $file && (($d) = stat(_)) && $d < 0) {
    2. print "$file is executable NFS file\n";
    3. }

    (This works on machines only for which the device number is negative under NFS.)

    On some platforms inode numbers are of a type larger than perl knows how to handle as integer numerical values. If necessary, an inode number will be returned as a decimal string in order to preserve the entire value. If used in a numeric context, this will be converted to a floating-point numerical value, with rounding, a fate that is best avoided. Therefore, you should prefer to compare inode numbers using eq rather than == . eq will work fine on inode numbers that are represented numerically, as well as those represented as strings.

    Because the mode contains both the file type and its permissions, you should mask off the file type portion and (s)printf using a "%o" if you want to see the real permissions.

    1. my $mode = (stat($filename))[2];
    2. printf "Permissions are %04o\n", $mode & 07777;

    In scalar context, stat returns a boolean value indicating success or failure, and, if successful, sets the information associated with the special filehandle _ .

    The File::stat module provides a convenient, by-name access mechanism:

    1. use File::stat;
    2. my $sb = stat($filename);
    3. printf "File is %s, size is %s, perm %04o, mtime %s\n",
    4. $filename, $sb->size, $sb->mode & 07777,
    5. scalar localtime $sb->mtime;

    You can import symbolic mode constants (S_IF* ) and functions (S_IS* ) from the Fcntl module:

    1. use Fcntl ':mode';
    2. my $mode = (stat($filename))[2];
    3. my $user_rwx = ($mode & S_IRWXU) >> 6;
    4. my $group_read = ($mode & S_IRGRP) >> 3;
    5. my $other_execute = $mode & S_IXOTH;
    6. printf "Permissions are %04o\n", S_IMODE($mode), "\n";
    7. my $is_setuid = $mode & S_ISUID;
    8. my $is_directory = S_ISDIR($mode);

    You could write the last two using the -u and -d operators. Commonly available S_IF* constants are:

    1. # Permissions: read, write, execute, for user, group, others.
    2. S_IRWXU S_IRUSR S_IWUSR S_IXUSR
    3. S_IRWXG S_IRGRP S_IWGRP S_IXGRP
    4. S_IRWXO S_IROTH S_IWOTH S_IXOTH
    5. # Setuid/Setgid/Stickiness/SaveText.
    6. # Note that the exact meaning of these is system-dependent.
    7. S_ISUID S_ISGID S_ISVTX S_ISTXT
    8. # File types. Not all are necessarily available on
    9. # your system.
    10. S_IFREG S_IFDIR S_IFLNK S_IFBLK S_IFCHR
    11. S_IFIFO S_IFSOCK S_IFWHT S_ENFMT
    12. # The following are compatibility aliases for S_IRUSR,
    13. # S_IWUSR, and S_IXUSR.
    14. S_IREAD S_IWRITE S_IEXEC

    and the S_IF* functions are

    1. S_IMODE($mode) the part of $mode containing the permission
    2. bits and the setuid/setgid/sticky bits
    3. S_IFMT($mode) the part of $mode containing the file type
    4. which can be bit-anded with (for example)
    5. S_IFREG or with the following functions
    6. # The operators -f, -d, -l, -b, -c, -p, and -S.
    7. S_ISREG($mode) S_ISDIR($mode) S_ISLNK($mode)
    8. S_ISBLK($mode) S_ISCHR($mode) S_ISFIFO($mode) S_ISSOCK($mode)
    9. # No direct -X operator counterpart, but for the first one
    10. # the -g operator is often equivalent. The ENFMT stands for
    11. # record flocking enforcement, a platform-dependent feature.
    12. S_ISENFMT($mode) S_ISWHT($mode)

    See your native chmod(2) and stat(2) documentation for more details about the S_* constants. To get status info for a symbolic link instead of the target file behind the link, use the lstat function.

    Portability issues: stat in perlport.