[AWK] color text with tcpdump example

For some people, they may want to see how much traffic is going over an interface with classified over IP addresses.
Here goes the awk script for that.
If the traffic is higher than WARN level, it will print it with blue color and higher than ERR lever, it will print it with red color.
BEGIN {
RESOL=1;
# LIMIT_WARN=500; # in Kbytes
# LIMIT_CRIT=1000; # in Kbytes

found_switches=0;
old_time = 0;

for( i=0; i<100; i++ ){
found_switch_list[i]=0;
sent_cnt[i]=0;
sent_bytes[i]=0;
}


switch_names[0]="NAME-1"
switch_ip_list[0]="192.168.1.1"

switch_name[1]="NAME-2"
switch_ip_list[1]="192.168.1.2"

switch_name[2]="NAME-3"
switch_ip_list[2]="192.168.1.3"


total_registered_switches=3

count_=0;
}

{

# parse switch ip and length
time=$1;
IP1=$3;
IP2=$5;

len = substr($9, 0, length($9)-1);

switch_ip=substr($10, 0, length($10)-6);


# resolve switch name
for( i = 0; i RESOL ) {

# every 10 seconds, we print the heading
if( count_ % 10 == 0 ) {
printf("#-------------------------------------------------------------------------------------------------------------------------------------------------------#\n");
for( i=0; i LIMIT_CRIT ) {
printf("\033[1;31m%12d KB/s\033[0m", sent_bytes[i]/1000);
}
else if( sent_bytes[i]/1000 > LIMIT_WARN ) {
printf("\033[1;34m%12d KB/s\033[0m", sent_bytes[i]/1000);
} else {
printf("%12d KB/s", sent_bytes[i]/1000);
}
sent_bytes[i]=0;
sent_cnt[i]=0;
}
printf("\n");


old_time = time;
}



}


save the above awk script with 'ip.awk' and make a shell script as the following

usage() {
echo "usage: $0 "
echo ""
echo "Example:"
echo " $0 eth0 100 1000"
echo ""
exit 1;
}
[ x = x$3 ] && usage

sudo tcpdump -i eth0 -ne port 6633 -tt | awk -v LIMIT_WARN=$2 -v LIMIT_CRIT=$3 -f awk-extract-ip.awk

and save the above shell script with the name 'traffic-meter.sh"