How do I get file creation and modification date/times?
Question:
What’s the best cross-platform way to get file creation and modification dates/times, that works on both Linux and Windows?
Answers:
In newer code you should probably use os.path.getmtime() (thanks, Christian Oudard).
But note that it returns a floating point value of time_t with fraction seconds (if your OS supports it).
You have a couple of choices. For one, you can use the os.path.getmtime
and os.path.getctime
functions:
import os.path, time
print("last modified: %s" % time.ctime(os.path.getmtime(file)))
print("created: %s" % time.ctime(os.path.getctime(file)))
Your other option is to use os.stat
:
import os, time
(mode, ino, dev, nlink, uid, gid, size, atime, mtime, ctime) = os.stat(file)
print("last modified: %s" % time.ctime(mtime))
Note: ctime()
does not refer to creation time on *nix systems, but rather the last time the inode data changed. (Thanks to kojiro for making that fact more clear in the comments by providing a link to an interesting blog post.)
There are two methods to get the mod time, os.path.getmtime() or os.stat(), but the ctime is not reliable cross-platform (see below).
os.path.getmtime()
getmtime(path)
Return the time of last modification of path. The return value is a number giving the
number of seconds since the epoch (see the time module). Raise os.error if the file does
not exist or is inaccessible. New in version 1.5.2. Changed in version 2.3: If
os.stat_float_times() returns True, the result is a floating point number.
os.stat()
stat(path)
Perform a stat() system call on the given path. The return value is an object whose
attributes correspond to the members of the stat structure, namely: st_mode (protection
bits), st_ino (inode number), st_dev (device), st_nlink (number of hard links), st_uid
(user ID of owner), st_gid (group ID of owner), st_size (size of file, in bytes),
st_atime (time of most recent access), st_mtime (time of most recent content
modification), st_ctime (platform dependent; time of most recent metadata change on Unix, or the time of creation on Windows):
>>> import os
>>> statinfo = os.stat('somefile.txt')
>>> statinfo
(33188, 422511L, 769L, 1, 1032, 100, 926L, 1105022698,1105022732, 1105022732)
>>> statinfo.st_size
926L
>>>
In the above example you would use statinfo.st_mtime or statinfo.st_ctime to get the mtime and ctime, respectively.
os.stat
returns a named tuple with st_mtime
and st_ctime
attributes. The modification time is st_mtime
on both platforms; unfortunately, on Windows, ctime
means “creation time”, whereas on POSIX it means “change time”. I’m not aware of any way to get the creation time on POSIX platforms.
>>> import os
>>> os.stat('feedparser.py').st_mtime
1136961142.0
>>> os.stat('feedparser.py').st_ctime
1222664012.233
>>>
os.stat
does include the creation time. There’s just no definition of st_anything for the element of os.stat()
that contains the time.
So try this:
os.stat('feedparser.py')[8]
Compare that with your create date on the file in ls -lah
They should be the same.
The best function to use for this is os.path.getmtime(). Internally, this just uses os.stat(filename).st_mtime
.
The datetime module is the best for manipulating timestamps, so you can get the modification date as a datetime
object like this:
import os
import datetime
def modification_date(filename):
t = os.path.getmtime(filename)
return datetime.datetime.fromtimestamp(t)
Usage example:
>>> d = modification_date('/var/log/syslog')
>>> print d
2009-10-06 10:50:01
>>> print repr(d)
datetime.datetime(2009, 10, 6, 10, 50, 1)
If the following symbolic links are not important, you can also use the os.lstat
builtin.
>>> os.lstat("2048.py")
posix.stat_result(st_mode=33188, st_ino=4172202, st_dev=16777218L, st_nlink=1, st_uid=501, st_gid=20, st_size=2078, st_atime=1423378041, st_mtime=1423377552, st_ctime=1423377553)
>>> os.lstat("2048.py").st_atime
1423378041.0
Getting some sort of modification date in a cross-platform way is easy – just call os.path.getmtime(path)
and you’ll get the Unix timestamp of when the file at path
was last modified.
Getting file creation dates, on the other hand, is fiddly and platform-dependent, differing even between the three big OSes:
- On Windows, a file’s
ctime
(documented at https://msdn.microsoft.com/en-us/library/14h5k7ff.aspx) stores its creation date. You can access this in Python through os.path.getctime()
or the .st_ctime
attribute of the result of a call to os.stat()
. This won’t work on Unix, where the ctime
is the last time that the file’s attributes or content were changed.
- On Mac, as well as some other Unix-based OSes, you can use the
.st_birthtime
attribute of the result of a call to os.stat()
.
-
On Linux, this is currently impossible, at least without writing a C extension for Python. Although some file systems commonly used with Linux do store creation dates (for example, ext4
stores them in st_crtime
) , the Linux kernel offers no way of accessing them; in particular, the structs it returns from stat()
calls in C, as of the latest kernel version, don’t contain any creation date fields. You can also see that the identifier st_crtime
doesn’t currently feature anywhere in the Python source. At least if you’re on ext4
, the data is attached to the inodes in the file system, but there’s no convenient way of accessing it.
The next-best thing on Linux is to access the file’s mtime
, through either os.path.getmtime()
or the .st_mtime
attribute of an os.stat()
result. This will give you the last time the file’s content was modified, which may be adequate for some use cases.
Putting this all together, cross-platform code should look something like this…
import os
import platform
def creation_date(path_to_file):
"""
Try to get the date that a file was created, falling back to when it was
last modified if that isn't possible.
See http://stackoverflow.com/a/39501288/1709587 for explanation.
"""
if platform.system() == 'Windows':
return os.path.getctime(path_to_file)
else:
stat = os.stat(path_to_file)
try:
return stat.st_birthtime
except AttributeError:
# We're probably on Linux. No easy way to get creation dates here,
# so we'll settle for when its content was last modified.
return stat.st_mtime
In Python 3.4 and above, you can use the object oriented pathlib module interface which includes wrappers for much of the os module. Here is an example of getting the file stats.
>>> import pathlib
>>> fname = pathlib.Path('test.py')
>>> assert fname.exists(), f'No such file: {fname}' # check that the file exists
>>> print(fname.stat())
os.stat_result(st_mode=33206, st_ino=5066549581564298, st_dev=573948050, st_nlink=1, st_uid=0, st_gid=0, st_size=413, st_atime=1523480272, st_mtime=1539787740, st_ctime=1523480272)
For more information about what os.stat_result
contains, refer to the documentation. For the modification time you want fname.stat().st_mtime
:
>>> import datetime
>>> mtime = datetime.datetime.fromtimestamp(fname.stat().st_mtime, tz=datetime.timezone.utc)
>>> print(mtime)
datetime.datetime(2018, 10, 17, 10, 49, 0, 249980)
If you want the creation time on Windows, or the most recent metadata change on Unix, you would use fname.stat().st_ctime
:
>>> ctime = datetime.datetime.fromtimestamp(fname.stat().st_ctime, tz=datetime.timezone.utc)
>>> print(ctime)
datetime.datetime(2018, 4, 11, 16, 57, 52, 151953)
This article has more helpful info and examples for the pathlib module.
import os, time, datetime
file = "somefile.txt"
print(file)
print("Modified")
print(os.stat(file)[-2])
print(os.stat(file).st_mtime)
print(os.path.getmtime(file))
print()
print("Created")
print(os.stat(file)[-1])
print(os.stat(file).st_ctime)
print(os.path.getctime(file))
print()
modified = os.path.getmtime(file)
print("Date modified: "+time.ctime(modified))
print("Date modified:",datetime.datetime.fromtimestamp(modified))
year,month,day,hour,minute,second=time.localtime(modified)[:-3]
print("Date modified: %02d/%02d/%d %02d:%02d:%02d"%(day,month,year,hour,minute,second))
print()
created = os.path.getctime(file)
print("Date created: "+time.ctime(created))
print("Date created:",datetime.datetime.fromtimestamp(created))
year,month,day,hour,minute,second=time.localtime(created)[:-3]
print("Date created: %02d/%02d/%d %02d:%02d:%02d"%(day,month,year,hour,minute,second))
prints
somefile.txt
Modified
1429613446
1429613446.0
1429613446.0
Created
1517491049
1517491049.28306
1517491049.28306
Date modified: Tue Apr 21 11:50:46 2015
Date modified: 2015-04-21 11:50:46
Date modified: 21/04/2015 11:50:46
Date created: Thu Feb 1 13:17:29 2018
Date created: 2018-02-01 13:17:29.283060
Date created: 01/02/2018 13:17:29
Note: A file’s ctime on Linux is slightly different than on Windows.
Windows users know theirs as "creation time".
Linux users know theirs as "change time".
It may worth taking a look at the crtime
library which implements cross-platform access to the file creation time.
from crtime import get_crtimes_in_dir
for fname, date in get_crtimes_in_dir(".", raise_on_error=True, as_epoch=False):
print(fname, date)
# file_a.py Mon Mar 18 20:51:18 CET 2019
I am a fan of pathlib.
from pathlib import Path
target = Path('out/soong/build.ninja')
mtime = target.stat().st_mtime
atime = target.stat().st_atime
ctime = target.stat().st_ctime
I believe this is also feasible for Windows Subsystem for Linux (WSL).
What’s the best cross-platform way to get file creation and modification dates/times, that works on both Linux and Windows?
In newer code you should probably use os.path.getmtime() (thanks, Christian Oudard).
But note that it returns a floating point value of time_t with fraction seconds (if your OS supports it).
You have a couple of choices. For one, you can use the os.path.getmtime
and os.path.getctime
functions:
import os.path, time
print("last modified: %s" % time.ctime(os.path.getmtime(file)))
print("created: %s" % time.ctime(os.path.getctime(file)))
Your other option is to use os.stat
:
import os, time
(mode, ino, dev, nlink, uid, gid, size, atime, mtime, ctime) = os.stat(file)
print("last modified: %s" % time.ctime(mtime))
Note: ctime()
does not refer to creation time on *nix systems, but rather the last time the inode data changed. (Thanks to kojiro for making that fact more clear in the comments by providing a link to an interesting blog post.)
There are two methods to get the mod time, os.path.getmtime() or os.stat(), but the ctime is not reliable cross-platform (see below).
os.path.getmtime()
getmtime(path)
Return the time of last modification of path. The return value is a number giving the
number of seconds since the epoch (see the time module). Raise os.error if the file does
not exist or is inaccessible. New in version 1.5.2. Changed in version 2.3: If
os.stat_float_times() returns True, the result is a floating point number.
os.stat()
stat(path)
Perform a stat() system call on the given path. The return value is an object whose
attributes correspond to the members of the stat structure, namely: st_mode (protection
bits), st_ino (inode number), st_dev (device), st_nlink (number of hard links), st_uid
(user ID of owner), st_gid (group ID of owner), st_size (size of file, in bytes),
st_atime (time of most recent access), st_mtime (time of most recent content
modification), st_ctime (platform dependent; time of most recent metadata change on Unix, or the time of creation on Windows):
>>> import os
>>> statinfo = os.stat('somefile.txt')
>>> statinfo
(33188, 422511L, 769L, 1, 1032, 100, 926L, 1105022698,1105022732, 1105022732)
>>> statinfo.st_size
926L
>>>
In the above example you would use statinfo.st_mtime or statinfo.st_ctime to get the mtime and ctime, respectively.
os.stat
returns a named tuple with st_mtime
and st_ctime
attributes. The modification time is st_mtime
on both platforms; unfortunately, on Windows, ctime
means “creation time”, whereas on POSIX it means “change time”. I’m not aware of any way to get the creation time on POSIX platforms.
>>> import os
>>> os.stat('feedparser.py').st_mtime
1136961142.0
>>> os.stat('feedparser.py').st_ctime
1222664012.233
>>>
os.stat
does include the creation time. There’s just no definition of st_anything for the element of os.stat()
that contains the time.
So try this:
os.stat('feedparser.py')[8]
Compare that with your create date on the file in ls -lah
They should be the same.
The best function to use for this is os.path.getmtime(). Internally, this just uses os.stat(filename).st_mtime
.
The datetime module is the best for manipulating timestamps, so you can get the modification date as a datetime
object like this:
import os
import datetime
def modification_date(filename):
t = os.path.getmtime(filename)
return datetime.datetime.fromtimestamp(t)
Usage example:
>>> d = modification_date('/var/log/syslog')
>>> print d
2009-10-06 10:50:01
>>> print repr(d)
datetime.datetime(2009, 10, 6, 10, 50, 1)
If the following symbolic links are not important, you can also use the os.lstat
builtin.
>>> os.lstat("2048.py")
posix.stat_result(st_mode=33188, st_ino=4172202, st_dev=16777218L, st_nlink=1, st_uid=501, st_gid=20, st_size=2078, st_atime=1423378041, st_mtime=1423377552, st_ctime=1423377553)
>>> os.lstat("2048.py").st_atime
1423378041.0
Getting some sort of modification date in a cross-platform way is easy – just call os.path.getmtime(path)
and you’ll get the Unix timestamp of when the file at path
was last modified.
Getting file creation dates, on the other hand, is fiddly and platform-dependent, differing even between the three big OSes:
- On Windows, a file’s
ctime
(documented at https://msdn.microsoft.com/en-us/library/14h5k7ff.aspx) stores its creation date. You can access this in Python throughos.path.getctime()
or the.st_ctime
attribute of the result of a call toos.stat()
. This won’t work on Unix, where thectime
is the last time that the file’s attributes or content were changed. - On Mac, as well as some other Unix-based OSes, you can use the
.st_birthtime
attribute of the result of a call toos.stat()
. -
On Linux, this is currently impossible, at least without writing a C extension for Python. Although some file systems commonly used with Linux do store creation dates (for example,
ext4
stores them inst_crtime
) , the Linux kernel offers no way of accessing them; in particular, the structs it returns fromstat()
calls in C, as of the latest kernel version, don’t contain any creation date fields. You can also see that the identifierst_crtime
doesn’t currently feature anywhere in the Python source. At least if you’re onext4
, the data is attached to the inodes in the file system, but there’s no convenient way of accessing it.The next-best thing on Linux is to access the file’s
mtime
, through eitheros.path.getmtime()
or the.st_mtime
attribute of anos.stat()
result. This will give you the last time the file’s content was modified, which may be adequate for some use cases.
Putting this all together, cross-platform code should look something like this…
import os
import platform
def creation_date(path_to_file):
"""
Try to get the date that a file was created, falling back to when it was
last modified if that isn't possible.
See http://stackoverflow.com/a/39501288/1709587 for explanation.
"""
if platform.system() == 'Windows':
return os.path.getctime(path_to_file)
else:
stat = os.stat(path_to_file)
try:
return stat.st_birthtime
except AttributeError:
# We're probably on Linux. No easy way to get creation dates here,
# so we'll settle for when its content was last modified.
return stat.st_mtime
In Python 3.4 and above, you can use the object oriented pathlib module interface which includes wrappers for much of the os module. Here is an example of getting the file stats.
>>> import pathlib
>>> fname = pathlib.Path('test.py')
>>> assert fname.exists(), f'No such file: {fname}' # check that the file exists
>>> print(fname.stat())
os.stat_result(st_mode=33206, st_ino=5066549581564298, st_dev=573948050, st_nlink=1, st_uid=0, st_gid=0, st_size=413, st_atime=1523480272, st_mtime=1539787740, st_ctime=1523480272)
For more information about what os.stat_result
contains, refer to the documentation. For the modification time you want fname.stat().st_mtime
:
>>> import datetime
>>> mtime = datetime.datetime.fromtimestamp(fname.stat().st_mtime, tz=datetime.timezone.utc)
>>> print(mtime)
datetime.datetime(2018, 10, 17, 10, 49, 0, 249980)
If you want the creation time on Windows, or the most recent metadata change on Unix, you would use fname.stat().st_ctime
:
>>> ctime = datetime.datetime.fromtimestamp(fname.stat().st_ctime, tz=datetime.timezone.utc)
>>> print(ctime)
datetime.datetime(2018, 4, 11, 16, 57, 52, 151953)
This article has more helpful info and examples for the pathlib module.
import os, time, datetime
file = "somefile.txt"
print(file)
print("Modified")
print(os.stat(file)[-2])
print(os.stat(file).st_mtime)
print(os.path.getmtime(file))
print()
print("Created")
print(os.stat(file)[-1])
print(os.stat(file).st_ctime)
print(os.path.getctime(file))
print()
modified = os.path.getmtime(file)
print("Date modified: "+time.ctime(modified))
print("Date modified:",datetime.datetime.fromtimestamp(modified))
year,month,day,hour,minute,second=time.localtime(modified)[:-3]
print("Date modified: %02d/%02d/%d %02d:%02d:%02d"%(day,month,year,hour,minute,second))
print()
created = os.path.getctime(file)
print("Date created: "+time.ctime(created))
print("Date created:",datetime.datetime.fromtimestamp(created))
year,month,day,hour,minute,second=time.localtime(created)[:-3]
print("Date created: %02d/%02d/%d %02d:%02d:%02d"%(day,month,year,hour,minute,second))
prints
somefile.txt
Modified
1429613446
1429613446.0
1429613446.0
Created
1517491049
1517491049.28306
1517491049.28306
Date modified: Tue Apr 21 11:50:46 2015
Date modified: 2015-04-21 11:50:46
Date modified: 21/04/2015 11:50:46
Date created: Thu Feb 1 13:17:29 2018
Date created: 2018-02-01 13:17:29.283060
Date created: 01/02/2018 13:17:29
Note: A file’s ctime on Linux is slightly different than on Windows.
Windows users know theirs as "creation time".
Linux users know theirs as "change time".
It may worth taking a look at the crtime
library which implements cross-platform access to the file creation time.
from crtime import get_crtimes_in_dir
for fname, date in get_crtimes_in_dir(".", raise_on_error=True, as_epoch=False):
print(fname, date)
# file_a.py Mon Mar 18 20:51:18 CET 2019
I am a fan of pathlib.
from pathlib import Path
target = Path('out/soong/build.ninja')
mtime = target.stat().st_mtime
atime = target.stat().st_atime
ctime = target.stat().st_ctime
I believe this is also feasible for Windows Subsystem for Linux (WSL).