#!/usr/bin/perl 
use strict;
#Declare Functions
#
#Declare Variables
#
# Variables used in Main Section
my $file = ""; # for file name
my $dir = ""; # for directory name
my $pat = ""; # for search pattern
my $count = 0; # for counting number of pattern occurences
my @word = []; # array of  words
my @lines = []; # array of lines
my $line = ""; # element in array lines
my $word = ""; # element in array word 
my @new2 = []; # array of second pattern
my @new3 = []; # array of third pattern
my $new2 = ""; # intial element of array of second pattern
my $d = ""; # for evaluating elements in a date array
my @date = []; # array of dates
my $date = ""; # initialize date element string
my $pat2 = ""; # initialize seoncd pateern  element string
my $date1 = ""; # initialize date alternative format element string
my $num = ""; # initialize numeric value  element string
my $new2 = ""; # initialize new second pattern  element string


#
# Usage:   perlprocfile  file_name   
#              file_name  will be the name of the file to process 
#              

{
#Opening files and reading data and doing something with it.

	$file = shift(@ARGV);
# Check for existence of file if the NOT (bang operand) is true
# that means there was no filename passed
       
        if(!$file ) {
           print "Usage:   perlprocfile  file_name \n";
           print " You forgot to enter a file to process \n";
           exit;
        }
	
	open(FILE,$file) || die "Couldn't open file $! \n";
	chop(@lines = <FILE>);
	close(FILE);
	
	print "Reading File $file ....Wait\n";

        print "The contents of the file are:\n";

	print "\n";

        foreach $line (@lines){
		print $line, "\n";
        }
        print "\n";

        print "Checking for bear's....\n";


#Searching for a particular pattern or string
#Parsing Strings
# initialize count to 0 and set pattern to search for as "bear"

	  $count = 0;
	  $pat = "bear";
	  foreach $line (@lines) {
             @word = split(/\s/,$line);
	         foreach $word(@word){
	  	 if($word eq $pat){
		    $count++;
		 } 
	     }
	   }	 
	  print "There are ", $count, " `$pat`  in the file. \n";
}
print "\n";

# How to use standard Unix commands in Perl

print "Current Working directory is ", `pwd`, "\n";
$dir = `pwd`;
$pat2 = "/";

@new2 = split(/$pat2/,$dir);
@new3 = split(/\//,$dir);
#print @new2, "\n";
#print @new3, "\n";
print "Splitting path into different directory names ...\n";  
foreach $new2 (@new2) {
print $new2, "\n";
}
print "\n";
# While loop

$num = 10;

print "Counting number of sub directories to current directory ....\n";

while($num > $#new2) {
$num--;
}
print "Total count = ", $num, "\n";
print "\n";

# Use of subroutines, passing data to and fro, etc.
# Call Subroutine sub2 passing no parameters. 
&sub2;

# Variable $date1 is evaluated in Sub2

print "Today is ", $date1,"\n";
print "Splitting date into it's constituents ...\n";
@date = split(/\s/,$date1);

foreach $d (@date){
print "d = ", $d,"\n";
}
print "\n";
# How to pass variables to subroutines?
# Call Subroutine sub3 passing the "date array" as a parameter
&sub3(@date);
exit;
#
# End Main Section
#
#
# Subroutine Section ************************************
# Subroutine Sub2
# Returns today's date from  built in `date` system function
# as an array.
#
sub sub2{
$date1 = `date`;

#return $date1 to the main calling routine
$date1;

}
# ******* End Subroutine sub2
#
# Subroutine sub3
# Note input is passed in as an array which is a split string, because of
# a slight bug in the algorithm, we need the $filler because a single digit
# as in 3 Febuary will be changed to a SPACE character in the filler array.
# You can see this in the previous output of this program.
# Notice how variable are declared as locally as possible. They are defined 
# here instead of in the main section.
#
sub sub3 {
my $day_of_week = ""; # initialize day of week element string
my $month = ""; # initialize month  element string
my $filler = ""; # initialize filler  element string
my $day_number = ""; # initialize day number element string
my $time = ""; # initialize time element string
my $zone = ""; # initialize zone element string
my $year = ""; # initialize year element string

# Get input from the default array variable @_
($day_of_week, $month,$filler,$day_number , $time,$zone,$year) = @_;

print "Thank you for being with us on this day number $day_number \n";
print "in month $month on this day $day_of_week at  $time $zone";
print " in the year $year \n";
}
# End Subroutine sub3    **************************
#
# End Subroutine Section **************************
exit;