hi there am new to bash shell programming.. i need help with to write a program where the shell will read a file called hostfile.txt where address are contain and ping it with timeout option of 5 seconds.. i need to use a while loop and read the host file

Show us what you've got so far. you might want to read these:
http://tldp.org/LDP/Bash-Beginners-G...tml/index.html
http://rute.2038bug.com/index.html.gz

These are the codes..and I am sure you will find out how to input the file.
# ! /bin/bash

LAST=254

echo -n "Enter first 3 Octets of the Range that you want to Scan :"
read range
for ((ip=1; ip <=LAST; ip++))
do
ping -c 1 -w 1 $range.$ip > /dev/null
if [ $? -eq "0" ];then
echo "$range.$ip is alive"
else
echo "$range.$ip is not reachable"
fi
done

OR
# !/bin/bash
echo -n "Enter first 3 Octets of the Range that you want to Scan : "
read range
#for ip in $(seq 1 254);do
for ip in {1..254};do

ping -c 1 $range.$ip > /dev/null
if [ $? -eq "0" ];then
echo "$range.$ip is alive"
else
echo "$range.$ip is not reachable"
fi
done