Shell Programming and Scripting

#!/bin/bash
CONNECTED=$(netstat -a | grep -c 1.1.1.1)
while [echo $CONNECTED -gt 0]; do
  echo -n p >/dev/ttyS1;
  sleep 20;
done

#!/bin/bash
CONNECTED=$(netstat -a | grep -c 1.1.1.1)
while [ "$CONNECTED" -gt 0 ]; do
echo -n p >/dev/ttyS1;
sleep 20;
CONNECTED=$(netstat -a | grep -c 1.1.1.1)#I think you need this also inside the while loop. so it can change the value and reflects it..
done

while netstat -antu|grep  -q 10.1.1.1; do something; done

#!/bin/bash
CONNECTED=$(ps -ef | grep -c APP1)
while [ "$CONNECTED" -gt 1 ]; do
  echo -n p >/dev/ttyS1;
  echo $CONNECTED
  sleep 10;
  CONNECTED=$(ps -ef | grep -c APP1)
done