stat —- Interpreting stat() results

源代码：Lib/stat.py

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

在 3.4 版更改: The stat module is backed by a C implementation.

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

• stat.SISDIR(_mode)
• Return non-zero if the mode is from a directory.

• stat.SISCHR(_mode)
• Return non-zero if the mode is from a character special device file.

• stat.SISBLK(_mode)
• Return non-zero if the mode is from a block special device file.

• stat.SISREG(_mode)
• Return non-zero if the mode is from a regular file.

• stat.SISFIFO(_mode)
• Return non-zero if the mode is from a FIFO (named pipe).

• stat.SISLNK(_mode)
• Return non-zero if the mode is from a symbolic link.

• stat.SISSOCK(_mode)
• Return non-zero if the mode is from a socket.

• stat.SISDOOR(_mode)
• Return non-zero if the mode is from a door.

3.4 新版功能.

• stat.SISPORT(_mode)
• Return non-zero if the mode is from an event port.

3.4 新版功能.

• stat.SISWHT(_mode)
• Return non-zero if the mode is from a whiteout.

3.4 新版功能.

Two additional functions are defined for more general manipulation of the file'smode:

• stat.SIMODE(_mode)
• Return the portion of the file's mode that can be set byos.chmod()—-that is, the file's permission bits, plus the stickybit, set-group-id, and set-user-id bits (on systems that support them).

• stat.SIFMT(_mode)
• Return the portion of the file's mode that describes the file type (used by theS_IS*() functions above).

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

示例:

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.stat(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 humanreadable string:

• stat.filemode(mode)
• Convert a file's mode to a string of the form '-rwxrwxrwx'.

3.3 新版功能.

在 3.4 版更改: The function supports S_IFDOOR, S_IFPORT andS_IFWHT.

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

• stat.ST_MODE
• inode保护模式。

• stat.ST_INO
• Inode 号

• stat.ST_DEV
• Device inode resides on.

• stat.ST_NLINK
• Number of links to the inode.

• stat.ST_UID
• 所有者的用户ID。

• stat.ST_GID
• 所有者的用户组ID。

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

• stat.ST_ATIME
• 上次访问的时间。

• stat.ST_MTIME
• 上次修改的时间。

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

The interpretation of "file size" changes according to the file type. For plainfiles this is the size of the file in bytes. For FIFOs and sockets under mostflavors of Unix (including Linux in particular), the "size" is the number ofbytes waiting to be read at the time of the call to os.stat(),os.fstat(), or os.lstat(); this can sometimes be useful, especiallyfor polling one of these special files after a non-blocking open. The meaningof the size field for other character and block devices varies more, dependingon 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
• 套接字

• stat.S_IFLNK
• 符号链接。

• stat.S_IFREG
• 普通文件。

• stat.S_IFBLK
• 块设备

• stat.S_IFDIR
• 目录

• stat.S_IFCHR
• 字符设备。

• stat.S_IFIFO
• 先进先出

• stat.S_IFDOOR
• 门

3.4 新版功能.

• stat.S_IFPORT
• 事件端口。

3.4 新版功能.

• stat.S_IFWHT
• Whiteout.

3.4 新版功能.

注解

S_IFDOOR, S_IFPORT or S_IFWHT are defined as0 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
• 设置UID位。

• stat.S_ISGID
• Set-group-ID bit. This bit has several special uses. For a directoryit indicates that BSD semantics is to be used for that directory:files created there inherit their group ID from the directory, notfrom the effective group ID of the creating process, and directoriescreated there will also get the S_ISGID bit set. For afile 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 filein that directory can be renamed or deleted only by the owner of thefile, by the owner of the directory, or by a privileged process.

• stat.S_IRWXU
• 文件所有者权限的掩码。

• stat.S_IRUSR
• 所有者具有读取权限。

• stat.S_IWUSR
• 所有者具有写入权限。

• stat.S_IXUSR
• 所有者具有执行权限。

• stat.S_IRWXG
• 组权限的掩码。

• stat.S_IRGRP
• 组具有读取权限。

• stat.S_IWGRP
• 组具有写入权限。

• stat.S_IXGRP
• 组具有执行权限。

• stat.S_IRWXO
• 其他人（不在组中）的权限掩码。

• stat.S_IROTH
• 其他人具有读取权限。

• stat.S_IWOTH
• 其他人具有写入权限。

• stat.S_IXOTH
• 其他人具有执行权限。

• 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 groupexecution 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
• 不要转储文件。

• stat.UF_IMMUTABLE
• 文件不能更改。

• stat.UF_APPEND
• 文件只能附加到。

• stat.UF_OPAQUE
• 当通过联合堆栈查看时，目录是不透明的。

• stat.UF_NOUNLINK
• 文件不能重命名或删除。

• stat.UF_COMPRESSED
• 文件是压缩存储的（Mac OS X 10.6+）。

• stat.UF_HIDDEN
• 文件不能显示在GUI 中（Mac OS X 10.5+）。

• stat.SF_ARCHIVED
• 文件可能已存档。

• stat.SF_IMMUTABLE
• 文件不能更改。

• stat.SF_APPEND
• 文件只能附加到。

• stat.SF_NOUNLINK
• 文件不能重命名或删除。

• stat.SF_SNAPSHOT
• 文件有一个快照文件

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

On Windows, the following file attribute constants are available for use whentesting bits in the st_file_attributes member returned by os.stat().See the Windows API documentationfor 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

3.5 新版功能.