stat — Interpreting stat() results - Python 3.10.9 documentation 编辑

Source code: Lib/stat.py

The stat module defines constants and functions for interpreting the results of os.stat(), os.fstat() and os.lstat() (if they exist). For complete details about the stat(), fstat() and lstat() calls, consult the documentation for your system.

Changed in version 3.4: The stat module is backed by a C implementation.

The stat module defines the following functions to test for specific file types:

stat.S_ISDIR(mode): Return non-zero if the mode is from a directory.

stat.S_ISCHR(mode): Return non-zero if the mode is from a character special device file.

stat.S_ISBLK(mode): Return non-zero if the mode is from a block special device file.

stat.S_ISREG(mode): Return non-zero if the mode is from a regular file.

stat.S_ISFIFO(mode): Return non-zero if the mode is from a FIFO (named pipe).

stat.S_ISLNK(mode): Return non-zero if the mode is from a symbolic link.

stat.S_ISSOCK(mode): Return non-zero if the mode is from a socket.

stat.S_ISDOOR(mode)

Return non-zero if the mode is from a door.

New in version 3.4.

stat.S_ISPORT(mode)

Return non-zero if the mode is from an event port.

New in version 3.4.

stat.S_ISWHT(mode)

Return non-zero if the mode is from a whiteout.

New in version 3.4.

Two additional functions are defined for more general manipulation of the file’s mode:

stat.S_IMODE(mode): Return the portion of the file’s mode that can be set by os.chmod()—that is, the file’s permission bits, plus the sticky bit, set-group-id, and set-user-id bits (on systems that support them).

stat.S_IFMT(mode): Return the portion of the file’s mode that describes the file type (used by the S_IS*() functions above).

Normally, you would use the os.path.is*() functions for testing the type of a file; the functions here are useful when you are doing multiple tests of the same file and wish to avoid the overhead of the stat() system call for each test. These are also useful when checking for information about a file that isn’t handled by os.path, like the tests for block and character devices.

Example:

import os, sys
from stat import *

def walktree(top, callback):
    '''recursively descend the directory tree rooted at top,
       calling the callback function for each regular file'''

    for f in os.listdir(top):
        pathname = os.path.join(top, f)
        mode = os.lstat(pathname).st_mode
        if S_ISDIR(mode):
            # It's a directory, recurse into it
            walktree(pathname, callback)
        elif S_ISREG(mode):
            # It's a file, call the callback function
            callback(pathname)
        else:
            # Unknown file type, print a message
            print('Skipping %s' % pathname)

def visitfile(file):
    print('visiting', file)

if __name__ == '__main__':
    walktree(sys.argv[1], visitfile)

An additional utility function is provided to convert a file’s mode in a human readable string:

stat.filemode(mode)

Convert a file’s mode to a string of the form ‘-rwxrwxrwx’.

New in version 3.3.

Changed in version 3.4: The function supports S_IFDOOR, S_IFPORT and S_IFWHT.

All the variables below are simply symbolic indexes into the 10-tuple returned by os.stat(), os.fstat() or os.lstat().

stat.ST_MODE: Inode protection mode.

stat.ST_INO: Inode number.

stat.ST_DEV: Device inode resides on.

stat.ST_NLINK: Number of links to the inode.

stat.ST_UID: User id of the owner.

stat.ST_GID: Group id of the owner.

stat.ST_SIZE: Size in bytes of a plain file; amount of data waiting on some special files.

stat.ST_ATIME: Time of last access.

stat.ST_MTIME: Time of last modification.

stat.ST_CTIME: The “ctime” as reported by the operating system. On some systems (like Unix) is the time of the last metadata change, and, on others (like Windows), is the creation time (see platform documentation for details).

The interpretation of “file size” changes according to the file type. For plain files this is the size of the file in bytes. For FIFOs and sockets under most flavors of Unix (including Linux in particular), the “size” is the number of bytes waiting to be read at the time of the call to os.stat(), os.fstat(), or os.lstat(); this can sometimes be useful, especially for polling one of these special files after a non-blocking open. The meaning of the size field for other character and block devices varies more, depending on the implementation of the underlying system call.

The variables below define the flags used in the ST_MODE field.

Use of the functions above is more portable than use of the first set of flags:

stat.S_IFSOCK: Socket.

stat.S_IFLNK: Symbolic link.

stat.S_IFREG: Regular file.

stat.S_IFBLK: Block device.

stat.S_IFDIR: Directory.

stat.S_IFCHR: Character device.

stat.S_IFIFO: FIFO.

stat.S_IFDOOR

Door.

New in version 3.4.

stat.S_IFPORT

Event port.

New in version 3.4.

stat.S_IFWHT

Whiteout.

New in version 3.4.

Note

S_IFDOOR, S_IFPORT or S_IFWHT are defined as 0 when the platform does not have support for the file types.

The following flags can also be used in the mode argument of os.chmod():

stat.S_ISUID: Set UID bit.

stat.S_ISGID: Set-group-ID bit. This bit has several special uses. For a directory it indicates that BSD semantics is to be used for that directory: files created there inherit their group ID from the directory, not from the effective group ID of the creating process, and directories created there will also get the S_ISGID bit set. For a file that does not have the group execution bit (S_IXGRP) set, the set-group-ID bit indicates mandatory file/record locking (see also S_ENFMT).

stat.S_ISVTX: Sticky bit. When this bit is set on a directory it means that a file in that directory can be renamed or deleted only by the owner of the file, by the owner of the directory, or by a privileged process.

stat.S_IRWXU: Mask for file owner permissions.

stat.S_IRUSR: Owner has read permission.

stat.S_IWUSR: Owner has write permission.

stat.S_IXUSR: Owner has execute permission.

stat.S_IRWXG: Mask for group permissions.

stat.S_IRGRP: Group has read permission.

stat.S_IWGRP: Group has write permission.

stat.S_IXGRP: Group has execute permission.

stat.S_IRWXO: Mask for permissions for others (not in group).

stat.S_IROTH: Others have read permission.

stat.S_IWOTH: Others have write permission.

stat.S_IXOTH: Others have execute permission.

stat.S_ENFMT: System V file locking enforcement. This flag is shared with S_ISGID: file/record locking is enforced on files that do not have the group execution bit (S_IXGRP) set.

stat.S_IREAD: Unix V7 synonym for S_IRUSR.

stat.S_IWRITE: Unix V7 synonym for S_IWUSR.

stat.S_IEXEC: Unix V7 synonym for S_IXUSR.

The following flags can be used in the flags argument of os.chflags():

stat.UF_NODUMP: Do not dump the file.

stat.UF_IMMUTABLE: The file may not be changed.

stat.UF_APPEND: The file may only be appended to.

stat.UF_OPAQUE: The directory is opaque when viewed through a union stack.

stat.UF_NOUNLINK: The file may not be renamed or deleted.

stat.UF_COMPRESSED: The file is stored compressed (macOS 10.6+).

stat.UF_HIDDEN: The file should not be displayed in a GUI (macOS 10.5+).

stat.SF_ARCHIVED: The file may be archived.

stat.SF_IMMUTABLE: The file may not be changed.

stat.SF_APPEND: The file may only be appended to.

stat.SF_NOUNLINK: The file may not be renamed or deleted.

stat.SF_SNAPSHOT: The file is a snapshot file.

See the *BSD or macOS systems man page chflags(2) for more information.

On Windows, the following file attribute constants are available for use when testing bits in the st_file_attributes member returned by os.stat(). See the Windows API documentation for more detail on the meaning of these constants.

stat.FILE_ATTRIBUTE_ARCHIVE
stat.FILE_ATTRIBUTE_COMPRESSED
stat.FILE_ATTRIBUTE_DEVICE
stat.FILE_ATTRIBUTE_DIRECTORY
stat.FILE_ATTRIBUTE_ENCRYPTED
stat.FILE_ATTRIBUTE_HIDDEN
stat.FILE_ATTRIBUTE_INTEGRITY_STREAM
stat.FILE_ATTRIBUTE_NORMAL
stat.FILE_ATTRIBUTE_NOT_CONTENT_INDEXED
stat.FILE_ATTRIBUTE_NO_SCRUB_DATA
stat.FILE_ATTRIBUTE_OFFLINE
stat.FILE_ATTRIBUTE_READONLY
stat.FILE_ATTRIBUTE_REPARSE_POINT
stat.FILE_ATTRIBUTE_SPARSE_FILE
stat.FILE_ATTRIBUTE_SYSTEM
stat.FILE_ATTRIBUTE_TEMPORARY
stat.FILE_ATTRIBUTE_VIRTUAL: New in version 3.5.

On Windows, the following constants are available for comparing against the st_reparse_tag member returned by os.lstat(). These are well-known constants, but are not an exhaustive list.