CODEWITHSUNDEEP
pythonlinux
user823743
user823743

Reputation: 2172

ctime, atime, and mtime - How to interpret them?

I am writing a program in Python that requires comparison of atime, mtime, and ctime of several directories. For this purpose I am using os.stat("my_directory/"). What I get as a result is a string which includes these times. For a sample directory I have:

st_atime=1418911410L
st_mtime=1418911410L
st_ctime=1404656050L

My problem is that I have some confusion with these numbers. I would like to know if these numbers are convertible to actual time? or, if one number (lets say ctime) is smaller than the other (like atime), does it mean that ctime is earlier than atime or later? I have searched many websites to learn this, but my attempts went without a success. Could anyone help me? thanks in advance.

Upvotes: 15

Views: 23082

Answers (5)

Andy
Andy

Reputation: 50540

You can get something useful from this by using the stat module to interpret the stat() results and converting from the epoch to a datetime:

import os
import datetime

print datetime.datetime.fromtimestamp(os.stat(".").st_atime)

This prints out a datetime object showing the last time the current directory was accessed:

datetime.datetime(2014, 12, 17, 7, 19, 14, 947384)

Upvotes: 2

Arnab Nandy
Arnab Nandy

Reputation: 6692

Also strftime can do this apart from other examples,

time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(1418911410))

Upvotes: 3

Martijn Pieters
Martijn Pieters

Reputation: 1121366

Quoting the os.stat() function documentation:

Note: The exact meaning and resolution of the st_atime, st_mtime, and st_ctime attributes depend on the operating system and the file system. For example, on Windows systems using the FAT or FAT32 file systems, st_mtime has 2-second resolution, and st_atime has only 1-day resolution. See your operating system documentation for details.

For Linux, that system documentation is the stat (2) manpage:

struct timespec st_atim;  /* time of last access */
struct timespec st_mtim;  /* time of last modification */
struct timespec st_ctim;  /* time of last status change */

where timespec is defined in man time(2):

Its time represents seconds and nanoseconds since the Epoch.

where the Epoch is the UNIX Epoch. The higher the value, the more time has passed since that Epoch (which is the 1st of January 1970, midnight UTC).

The Python time module deals in time in the same way, and the datetime module has class methods that'll give you a datetime object from such a value as well:

>>> import datetime
>>> datetime.datetime.fromtimestamp(1418911410L)
datetime.datetime(2014, 12, 18, 14, 3, 30)

As you can see above, the three fields represent access time, modification time and status change time, respectively.

Upvotes: 11

Kevin
Kevin

Reputation: 30151

You can convert those timestamps to datetime objects with this Python code:

import datetime

datetime.datetime.fromtimestamp(1418911410L)  # or whatever number you have

Upvotes: 3

Marc B
Marc B

Reputation: 360572

ctime - the last time the file's inode was changed (e.g. permissions changed, file renamed, etc..)
mtime - last time the file's CONTENTS were changed
atime - last time the file was accessed.

The numbers are simply unix timestamps - signed 32bit ints representing seconds since Jan 1/1970, aka the epoch.

And yes, smaller numbers = earlier in time.

Upvotes: 19

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