On Wed, Nov 26, 2008 at 10:01, Sharan Basappa <[EMAIL PROTECTED]> wrote:
> Hi,
>
> I am writing a scheduler for some proprietary task.
> There are two questions pertaining to this
>
> 1) I have to wait for creation of a file by some external process. How
> do I do that in perl?
> In other words, is it possible to list out the files in perl?
>
> 2) If file is not created then I have to wait for sometime. How do I
> put real time delay in perl?
snip
I would say something like
#!/usr/bin/perl
use strict;
use warnings;
#how long to wait before checking again
use constant WAIT => 1;
#number of seconds that must go by with
#no changes to the file for it to be
#considered closed
use constant NO_CHANGE_IN_FILE_FOR_X_SECONDS => 60;
die "usage: $0 file_to_wait_for\n" unless @ARGV == 1;
my $file = shift;
print "looking for $file\n";
#wait for the file to show up
sleep WAIT until -f $file;
print "file exists, waiting to see if it changes\n";
my $time = 0;
my $size = (stat $file)[7];
until ($time == NO_CHANGE_IN_FILE_FOR_X_SECONDS) {
if ($size == (stat $file)[7]) {
$time++;
} else {
$time = 0;
$size = (stat _)[7]; #reuse last stat call's buffer
}
sleep WAIT;
}
print "file hasn't changed for $time seconds, assuming it is closed\n";
#FIXME: possibly add some code using flock to see if there is an advisory
#lock on the file, but that is only needed if we know that locking is
#being used
--
Chas. Owens
wonkden.net
The most important skill a programmer can have is the ability to read.
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