Shell Programming and Scripting

$
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$ cat lines.txt
Microsoft,IBM,Oracle,Apple
Windows 95,DB2,Oracle,MacBook
MS Excel,Fortran,Siebel,iPod
XBox,ATM,MySQL,iPad
Zune,Deep Blue,PeopleSoft,Pixar
$
$
$ cat -n lines2.pl
     1  #perl -w
     2  use strict;
     3  # ##################################################################################################
     4  #
     5  #  For the data file that looks like this:
     6  #
     7  #  Microsoft,IBM,Oracle,Apple
     8  #  Windows 95,DB2,Oracle,MacBook
     9  #  MS Excel,Fortran,Siebel,iPod
    10  #  XBox,ATM,MySQL,iPad
    11  #  Zune,Deep Blue,PeopleSoft,Pixar
    12  #
    13  #  this Perl program creates a hash %all_comp_products that looks like this:
    14  #
    15  #  $all_comp_products{Microsoft} = [ "Windows 95", "MS Excel", "XBox",  "Zune"       ]
    16  #  $all_comp_products{IBM}       = [ "DB2",        "Fortran",  "ATM",   "Deep Blue"  ]
    17  #  $all_comp_products{Oracle}    = [ "Oracle",     "Siebel",   "MySQL", "PeopleSoft" ]
    18  #  $all_comp_products{Apple}     = [ "MacBook",    "iPod",     "iPad",  "Pixar"      ]
    19  #
    20  # ##################################################################################################
    21
    22  my $file = "lines.txt";
    23  my @company;
    24  my @values;
    25  my %all_comp_products;
    26  my %keyorder;
    27
    28  open (FH, "<", $file) or die "Can't open $file for reading: $!";
    29  while (<FH>) {
    30    chomp;
    31    if (/^Microsoft/) {
    32      @company = split /,/;
    33    } else {
    34      @values = split /,/;
    35      for (my $i = 0; $i <= $#company; $i++) {
    36        push @{$all_comp_products{$company[$i]}}, $values[$i];
    37      }
    38    }
    39  }
    40  close (FH) or die "Can't close $file: $!";
    41
    42  # Our custom key order is as follows -
    43  %keyorder = qw (Oracle 1 Apple 2 IBM 3 Microsoft 4);
    44
    45  # Now, we'll iterate through the hash with custom sorted key order and display the data
    46  foreach my $comp (sort {$keyorder{$a} <=> $keyorder{$b}} keys %all_comp_products ) {
    47    print "Company  : $comp\n";
    48    print "Products :\n";
    49    foreach my $prod (@{$all_comp_products{$comp}}) {
    50      print "           $prod\n";
    51    }
    52    print "=" x 40,"\n";
    53  }
$
$
$ perl lines2.pl
Company  : Oracle
Products :
           Oracle
           Siebel
           MySQL
           PeopleSoft
========================================
Company  : Apple
Products :
           MacBook
           iPod
           iPad
           Pixar
========================================
Company  : IBM
Products :
           DB2
           Fortran
           ATM
           Deep Blue
========================================
Company  : Microsoft
Products :
           Windows 95
           MS Excel
           XBox
           Zune
========================================
$
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