#!/usr/bin/perl                                                                 
BEGIN {push @INC, '/www/cgi-bin'};                                              
use perlfunc;                                                                   
                                                        
my $filename = '/tmp/snrlog';                          
my $MAXLINES=48960;  # 17bytes * 60mins * 24 hours * 2 days   

($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst)=localtime(time);          
$d = sprintf ("%02d:%02d:%02d", $hour, $min, $sec);                             
($s, $n) = get_wifi_signal(get_interface("wifi"));                              
$s = $n if $s eq "N/A";
                                      
open(my $fh, '>>', $filename) or die "Could not open file '$filename' $!";    
print $fh "$d,$s,$n\n";                                                         
close $fh;                                                                      
                                                                                
$lcount=`wc -l < $filename`;                                                    
chomp($lcount);                                                                 
                                                                                
if($lcount>$MAXLINES)                                                           
{                                                                               
        $rc=`tail -n$MAXLINES $filename > $filename.tmp`;                    
        $rc=`mv $filename.tmp $filename`;                                    
}