Hi Saras,
It's very simple create a text file with all country names(each in a new line)
suppose that file name is "country.txt"
$country_arr=file("country.txt");
for($i=0;$i<sizeof($country_arr);$i++)
{
$country=$country_arr[$i];
echo "$country";
}
Note: if the file is in some other location give the path