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11.4. stat — Interpreting stat() results
- Source code: Modules/_stat.c
- 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.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 covert 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.
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 (Mac OS X 10.6+).
- stat.UF_HIDDEN
The file should not be displayed in a GUI (Mac OS X 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 Mac OS systems man page chflags(2) for more information.