Re: Searching for a file

"Peter J. Holzer" <[email protected]> Sat, 9 Aug 2025 20:35:45 +0200

Newsgroups	gmane.comp.python.general
Message-ID	<[email protected]>

On 2025-08-04 19:22:23 -0600, Michael Torrie via Python-list wrote:
> On 5/24/25 7:19 PM, Chris Angelico via Python-list wrote:
> > for dir in dirs:
> >     try: open(dir + "/" + fn).close()
> >     except FileNotFoundError: pass
> >     else: break
> > 
> > Is this really all that difficult? Not everything has to be in the stdlib.
> 
> That would modify atime on unix file systems, no?

No, you have to actually read the file for that. Just opening is not
enough:

    % ls -lu foo
    -rw-r--r-- 1 hjp hjp 56 May 28 10:05 foo
    % python3
    Python 3.12.3 (main, Jun 18 2025, 17:59:45) [GCC 13.3.0] on linux
    Type "help", "copyright", "credits" or "license" for more information.
    >>> fh = open("foo")
    >>> fh.close()
    >>>
    % ls -lu foo
    -rw-r--r-- 1 hjp hjp 56 May 28 10:05 foo

Still unchanged. But:

% python3
Python 3.12.3 (main, Jun 18 2025, 17:59:45) [GCC 13.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> fh = open("foo")
>>> s = fh.read()
>>> fh.close()
>>>
% ls -lu foo
-rw-r--r-- 1 hjp hjp 56 Aug  9 20:31 foo

Now the atime is changed.

> Of course most modern file systems on SSDs are mounted with noatime,
> but still.

relatime is probably more common. And definitely more useful.

        hjp

-- 
   _  | Peter J. Holzer    | Story must make more sense than reality.
|_|_) |                    |
| |   | [email protected]         |    -- Charles Stross, "Creative writing
__/   | http://www.hjp.at/ |       challenge!"

signature.asc (application/pgp-signature, 833 B)