1. $_ : The default input and pattern-searching space.
Example 1:
my @array_variable = (1 2 3 4);
foreach (@array_variable){
print $_."\n"; # $_ will get the value 1,2,3,4 in loop, if no other variable is supplied.
}
Example 2:
while (<FH>){
chomp($_); # $_ re...
