how to find a file's age with respect to current time 1

[gftech]

Hi,

I've used the -M operator to find a file's age in days. However, -M returns the age with respect to the program start time. Now that I plan to run my program as a daemon, I need to find a file's age wrt the *current* time. Any body out there knows how I can do that?

Thanks & regards,

 

[travs69]

-M returns the files agein days. It has nothing to do with the start time of your program.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Travis - Those who say it cannot be done are usually interrupted by someone else doing it; Give the wrong symptoms, get the wrong solutions;

 

[brigmar]

travs:

http://perldoc.perl.org/functions/-X.html

"-M Script start time minus file modification time, in days."

 

[travs69]

Well I guess I was thinking the file time that created the file.. yeah that's it

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Travis - Those who say it cannot be done are usually interrupted by someone else doing it; Give the wrong symptoms, get the wrong solutions;

 

[travs69]

Well screwed up that joke to.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Travis - Those who say it cannot be done are usually interrupted by someone else doing it; Give the wrong symptoms, get the wrong solutions;

 

[travs69]

Anyway.. how about a real answer

http://perldoc.perl.org/search.html?q=stat

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Travis - Those who say it cannot be done are usually interrupted by someone else doing it; Give the wrong symptoms, get the wrong solutions;

 

[brigmar]

gftech,
Use the stat() function :

http://perldoc.perl.org/functions/stat.html

It returns an array, the 10th element ( [9] ) of which is the modify timestamp wrt the epoch.
Subtract that from the current time to get the file age in seconds.

 

[KevinADC]

the script start time is generally so close to the current time it does not matter. But in a long running program you want to use stat().

------------------------------------------
- Kevin, perl coder unexceptional!

 

[travs69]

Yeah I think he was saying he was going to daemonize it.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Travis - Those who say it cannot be done are usually interrupted by someone else doing it; Give the wrong symptoms, get the wrong solutions;

 

[rvBasic]

May I contribute my little bit of confusion? Both -M and stats return a time interval since the file was last modified - not created. According to the Perl Cookbook p.347

There is no way under standard Unix to find a file's creation time.

If you really want that date you're apparently stuck. I wonder if the same restriction applies to Win systems?

It is also my understanding that -M returns a value measured in days, whilst stats return a value measured in seconds.

_________________________________
In theory, there is no difference between theory and practice. In practice, there is. [attributed to Yogi Berra]

 

[gftech]

Thank you all for your inputs. I went stat() and solved my problem:

# get cur time
`touch curtime`
my $curtime = (stat("curtime"))[9];
unlink "curtime";
# find file age
if (($curtime - (stat($thefile))[9]) > AGE) {
# process $thefile
}

 

[brigmar]

You don't need to touch a file to find the current time.
the function time returns the number of seconds since the epoch.

if( time - stat($thefile)[9] > AGE ) {
  # process the file
}

 

[gftech]

Thanks brigmar, your piece is cool!