this is a (stupid) counter i wrote for exercise
years ago: maybe it could help you...
!/usr/bin/perl -w
use Fcntl qw(:flock);
my $filename = '/tmp/counter';
if(-e $filename) {
open FH, "+< $filename" || die "cannot open: $!";
}
else {
#first time...
open FH, "+> $filename" || die "cannot open: $!";
}
lock(FH);
my $count = <FH> || 0;
$count++;
seek FH, 0,0;
print FH $count;
unlock(FH);
print "$count\n";
sub lock {
my $fh = shift;
flock $fh, LOCK_EX;
}
sub unlock {
my $fh = shift;
flock $fh, LOCK_UN;
}
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