# File:	file3.pl			
# Title: Find pattern in a file. Print the lines where it finds the pattern
# Author:	Mihaela Malita
# Here is the file mary.txt: 
#			Mary had a little lamb,
#			It's fleece was white as snow.
#			And everywhere that Mary went
#			The lamb was sure to go....
#		Name of file? mary.txt
#		Find pattern? l..b	# means a word with 4 letters start with l ends with b
#		Lines where pattern is found:
#		1	Mary had a little lamb,
#		4	The lamb was sure to go.
#		8	To see a lamb at school.
use strict;		# all variables have to be declared with my 
use warnings; 	# gives warnings (same as >perl -w file3.pl )
my $filename;
print "Name of the file (mary.txt)? ";
$filename = <STDIN>;	chop($filename); 	#read from keyboard
unless (open(IN,"$filename")) {				#check if the file exists
	print "No file with such a name!";
	exit;
}
my $p; 	#declare variable with pattern (it can be just a word!)
print "Find pattern? ";
$p = <STDIN>;	chop($p);
print "Lines where the pattern $P is found:\n";
my $line;	# the line of the text
my $i = 0; 	# counts the lines
while ($line = <IN>) {			#reads line by line the text file until End Of File (EOF)
	$i = $i + 1;
	if   ( $line =~ /$p/ ) {	#prints lines with the pattern (regular expr)
		print "$i\t\t$line";
	}
}
close IN;
exit;