To estimate the frequency of web page surfing per hour every day from Apache access_log, a simple Perl programming is shown as follows:

#!/usr/bin/perl -w

open ( FH, "../../access_log.1" );
while ( )
{
chomp;
$_ =~ s/^.*?:(\d{2}):.*/$1/;
$hr{$_}++;
}
close( FH );
foreach ( sort keys %hr )
{
print "Hour $_ has $hr{$_} times access.\n";
}
--