Action Based on File's Last Modification Time: Is One Approach Better?

[James E Keenan]

Let's say that I wish to process every file in a given directory that was
last modified more than 14 days ago. From various parts of the Camel book,
it appears I could test the age of the file in 1 of 2 ways.

### approach using 'stat' ### Camel pp 800-801
my ($file, $days_ago, $DAY, $earlier);
$DAY = 60 * 60 * 24;
$days_ago = 14;
$earlier = time() - ($days_ago * $DAY);
....
if ( (stat($file))[9] < $earlier ) {
# process $file
}

### approach using file test operator '-M' ### Camel pp 98-100
if (-M $file > 14) {
# process $file
}

### [end code samples] ###
For the purpose of argument, let's assume that the "at the point the Perl
script started running" proviso for the file test operator is not meaningful
from the current time. Given that assumption, is there any particular
reason to prefer the more verbose approach using 'stat' to the simple one
using the '-M'?

jimk

 

[Steve Grazzini]

Let's say that I wish to process every file in a given directory
that was last modified more than 14 days ago. From various parts
of the Camel book, it appears I could test the age of the file in
1 of 2 ways.

[ using stat() and -M ]

For the purpose of argument, let's assume that the "at the point
the Perl script started running" proviso for the file test operator
is not meaningful from the current time.

This is what trips people, though, when they use it in long-running
daemons, mod_perl handlers, etc.

Given that assumption, is there any particular reason to prefer the
more verbose approach using 'stat' to the simple one using the '-M'?

No. -M is simpler, easier to read, and probably a bit faster.