use strict;
use warnings;

local $/ = ' ';
while ( <DATA> ) {
    print "$_\n" if ( /p/i );
}

__DATA__
CPAN stands for comprehensive Perl Archive Network.
^ and $ are used as anchors in a regular expression.
/pattern/ is a pattern match operator.
Perl is very easy to learn.
Enter 'H' or 'h' for help.