Source code:Lib/stat.py
Thestat module defines constants and functions for interpreting theresults ofos.stat(),os.fstat() andos.lstat() (if theyexist). For complete details about thestat(),fstat() andlstat() calls, consult the documentation for your system.
Thestat module defines the following functions to test for specific filetypes:
Return non-zero if the mode is from a directory.
Return non-zero if the mode is from a character special device file.
Return non-zero if the mode is from a block special device file.
Return non-zero if the mode is from a regular file.
Return non-zero if the mode is from a FIFO (named pipe).
Return non-zero if the mode is from a symbolic link.
Return non-zero if the mode is from a socket.
Two additional functions are defined for more general manipulation of the file’smode:
Return the portion of the file’s mode that can be set byos.chmod()—that is, the file’s permission bits, plus the sticky bit, set-group-id, andset-user-id bits (on systems that support them).
Return the portion of the file’s mode that describes the file type (used by theS_IS*() functions above).
Normally, you would use theos.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 thestat() system callfor each test. These are also useful when checking for information about a filethat isn’t handled byos.path, like the tests for block and characterdevices.
Example:
importos,sysfromstatimport*defwalktree(top,callback):'''recursively descend the directory tree rooted at top, calling the callback function for each regular file'''forfinos.listdir(top):pathname=os.path.join(top,f)mode=os.stat(pathname).st_modeifS_ISDIR(mode):# It's a directory, recurse into itwalktree(pathname,callback)elifS_ISREG(mode):# It's a file, call the callback functioncallback(pathname)else:# Unknown file type, print a messageprint('Skipping %s'%pathname)defvisitfile(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 humanreadable string:
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 returnedbyos.stat(),os.fstat() oros.lstat().
Inode protection mode.
Inode number.
Device inode resides on.
Number of links to the inode.
User id of the owner.
Group id of the owner.
Size in bytes of a plain file; amount of data waiting on some special files.
Time of last access.
Time of last modification.
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 toos.stat(),os.fstat(), oros.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 theST_MODE field.
Use of the functions above is more portable than use of the first set of flags:
Socket.
Symbolic link.
Regular file.
Block device.
Directory.
Character device.
FIFO.
The following flags can also be used in themode argument ofos.chmod():
Set UID bit.
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 theS_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 alsoS_ENFMT).
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.
Mask for file owner permissions.
Owner has read permission.
Owner has write permission.
Owner has execute permission.
Mask for group permissions.
Group has read permission.
Group has write permission.
Group has execute permission.
Mask for permissions for others (not in group).
Others have read permission.
Others have write permission.
Others have execute permission.
System V file locking enforcement. This flag is shared withS_ISGID:file/record locking is enforced on files that do not have the groupexecution bit (S_IXGRP) set.
The following flags can be used in theflags argument ofos.chflags():
Do not dump the file.
The file may not be changed.
The file may only be appended to.
The directory is opaque when viewed through a union stack.
The file may not be renamed or deleted.
The file is stored compressed (Mac OS X 10.6+).
The file should not be displayed in a GUI (Mac OS X 10.5+).
The file may be archived.
The file may not be changed.
The file may only be appended to.
The file may not be renamed or deleted.
The file is a snapshot file.
See the *BSD or Mac OS systems man pagechflags(2) for more information.
11.2.fileinput — Iterate over lines from multiple input streams
11.4.filecmp — File and Directory Comparisons
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