What's up with File.ctime?

ruby-talk
1

Hello,
I need to notate the date/time attributes of files. I'm using File.ctime
and trimming it back to show just day, date, and time.

filetime = File.ctime(txtfile)
filetime = filetime.to_s.gsub!(/ -.*$/, "")

But, I've noticed that files that list in the directories as being dated
November 8 are showing via ctime as November 13 files. What's up?

Thanks,
Peter

···

--
Posted via http://www.ruby-forum.com/.

2

Perhaps dir/ls shows mtime? Try checking mtime/ctime/atime to see
which is the right one.
To display ctime on windows, try dir /T:C on unix ls -l --time=ctime

···

On 11/14/06, Peter Bailey <pbailey@bna.com> wrote:

Hello,
I need to notate the date/time attributes of files. I'm using File.ctime
and trimming it back to show just day, date, and time.

filetime = File.ctime(txtfile)
filetime = filetime.to_s.gsub!(/ -.*$/, "")

But, I've noticed that files that list in the directories as being dated
November 8 are showing via ctime as November 13 files. What's up?

3

Jan Svitok wrote:

···

On 11/14/06, Peter Bailey <pbailey@bna.com> wrote:

Hello,
I need to notate the date/time attributes of files. I'm using File.ctime
and trimming it back to show just day, date, and time.

filetime = File.ctime(txtfile)
filetime = filetime.to_s.gsub!(/ -.*$/, "")

But, I've noticed that files that list in the directories as being dated
November 8 are showing via ctime as November 13 files. What's up?

Perhaps dir/ls shows mtime? Try checking mtime/ctime/atime to see
which is the right one.
To display ctime on windows, try dir /T:C on unix ls -l --time=ctime

Thanks, Jan. Actually, I figured it out for myself. Looking deeper into
it, I found File.stat.mtime, and that's I'm using now, and it works.
.ctime, I guess, stands for "change time," so, it doesn't actually state
the timestamp of the file as it is. Thanks again.

--
Posted via http://www.ruby-forum.com/\.

4

> Hello,
> I need to notate the date/time attributes of files. I'm using File.ctime
> and trimming it back to show just day, date, and time.

        [...]

> But, I've noticed that files that list in the directories as being dated
> November 8 are showing via ctime as November 13 files. What's up?

Perhaps dir/ls shows mtime? Try checking mtime/ctime/atime to see
which is the right one.
To display ctime on windows, try dir /T:C on unix ls -l --time=ctime

ls -lu ;# => atime
ls -lc ;# => ctime
ls -l ;# => mtime

ctime means Inode modified, i.e. created, chmod'ed, etc. See man ls
if you're on unix. DIR /T:A gives access time according to XP docs.

        Hugh

···

On Tue, 14 Nov 2006, Jan Svitok wrote:

On 11/14/06, Peter Bailey <pbailey@bna.com> wrote:

5

Well, I thought ctime = creation time :wink: Now I've learned something as well.

···

On 11/14/06, Peter Bailey <pbailey@bna.com> wrote:

Jan Svitok wrote:
> On 11/14/06, Peter Bailey <pbailey@bna.com> wrote:
>> Hello,
>> I need to notate the date/time attributes of files. I'm using File.ctime
>> and trimming it back to show just day, date, and time.
>>
>> filetime = File.ctime(txtfile)
>> filetime = filetime.to_s.gsub!(/ -.*$/, "")
>>
>> But, I've noticed that files that list in the directories as being dated
>> November 8 are showing via ctime as November 13 files. What's up?
>
> Perhaps dir/ls shows mtime? Try checking mtime/ctime/atime to see
> which is the right one.
> To display ctime on windows, try dir /T:C on unix ls -l --time=ctime

Thanks, Jan. Actually, I figured it out for myself. Looking deeper into
it, I found File.stat.mtime, and that's I'm using now, and it works.
.ctime, I guess, stands for "change time," so, it doesn't actually state
the timestamp of the file as it is. Thanks again.

6

Hugh Sasse wrote:

···

On Tue, 14 Nov 2006, Jan Svitok wrote:

On 11/14/06, Peter Bailey <pbailey@bna.com> wrote:
> Hello,
> I need to notate the date/time attributes of files. I'm using File.ctime
> and trimming it back to show just day, date, and time.

        [...]

> But, I've noticed that files that list in the directories as being dated
> November 8 are showing via ctime as November 13 files. What's up?

Perhaps dir/ls shows mtime? Try checking mtime/ctime/atime to see
which is the right one.
To display ctime on windows, try dir /T:C on unix ls -l --time=ctime

ls -lu ;# => atime
ls -lc ;# => ctime
ls -l ;# => mtime

ctime means Inode modified, i.e. created, chmod'ed, etc. See man ls
if you're on unix. DIR /T:A gives access time according to XP docs.

        Hugh

Thanks, you guys. Nope, I'm on Windows. Yes, "dir /t:a" is probably the
equivalent to ctime, but, again, that's not what I want. I just want the
file time as it's listed in a garden-variety "dir."

--
Posted via http://www.ruby-forum.com/\.

7

Just to make things a little clearer:

the 'change' referenced by 'ctime' is a change to the inode (or metadata) for the file. So for example if the ownership or permissions of a file change then ctime will be updated. If the length of a file is changed (i.e. data is appended to the file) then ctime will change. The mtime field on the other hand only changes when data is written to the file (either new data appended to the end or existing data is modified).

Lots of people think ctime = 'creation time' but the Posix API doesn't actually provide access to a 'create time'.

I believe some Windows and Mac OS filesystems do have a notion of 'create time' that is recorded separately from the Posix 'ctime'. I don't know what the APIs are
to access that timestamp on those platforms.

Gary Wright

···

On Nov 14, 2006, at 9:50 AM, Jan Svitok wrote:

On 11/14/06, Peter Bailey <pbailey@bna.com> wrote:

Thanks, Jan. Actually, I figured it out for myself. Looking deeper into
it, I found File.stat.mtime, and that's I'm using now, and it works.
.ctime, I guess, stands for "change time," so, it doesn't actually state
the timestamp of the file as it is. Thanks again.

Well, I thought ctime = creation time :wink: Now I've learned something as well.