use strict;
use warnings;

# Open the file named file.txt. Abort if the file is unreadable.
my $filename = 'file.txt';
open my $file_handle, '<', $filename or die "Unable to open the file[$filename]!";

# a switch to hold if solar wind is found;
my $solar_wind_found_at_line = undef;

# Read the file line per line.
while ( my $line = <$file_handle> ){

		# remove the newline
		chomp $line;
		# print is your friend! is the first and powerful debug tool..
		print "DEBUG: line $. -->$line<--\n";
		# check for solar wind
		if ( $line =~ /solar winds/){
			# annotate the current line number
			$solar_wind_found_at_line = $.;
			print "DEBUG: 'solar wind' found at line $.\n";
			
		}
		
		# if (  $solar_wind_found_at_line IS DEFINED AND THE CURERENT LINE IS THE THIRD AFTER SOLAR WINDS   ){
		
			# REPLACE COUNTRY WITH PLACE (THIS CAN HAPPEN OR NOT)
			# RESET $solar_wind_found_at_line TO UNDEF (THIS MUST HAPPEN ANYWAY)
		# }
		
	# at the end the expected output
	print "OUTPUT DESIRED: [$line]\n\n"
}