Shell Programming and Scripting

    $line[$i] = lc($line[$i]);

    $line[$i] =~ s/\W/ /g;
    $line[$i] =~ s/\b[^ \t]\b//g;
    # Removes any word less than two letters.
    $line[$i] =~ s/[^a-z\n ]//g;

Test:desktop D2K$ perl working.pl 
#!/usr/bin/perl -w

use strict;

# This line will print a hello world line.
print "Hello world!\n";

exit 0;
      :    2 times, lines: 1,  5, 
   bin:    1 times, lines: 1, 
  exit:    1 times, lines: 8
 hello:    2 times, lines: 5, 
  line:    2 times, lines: 5, 
  perl:    1 times, lines: 1, 
 print:    2 times, lines: 5,  6, 
strict:    1 times, lines: 3, 
  this:    1 times, lines: 5, 
   use:    1 times, lines: 3, 
   usr:    1 times, lines: 1, 
  will:    1 times, lines: 5, 
 world:    2 times, lines: 5, 
Test:desktop D2K$

$
$ # Your input file
$ cat -n input.pl
     1  #!/usr/bin/perl -w
     2
     3  use strict;
     4
     5  # This line will print a hello world line.
     6  print "Hello world!\n";
     7
     8  exit 0;
$
$ # Your Perl program that processes your input file
$ # (This is "likely", since you haven't posted your Perl program).
$ cat -n process.pl
     1  #!perl -w
     2  my $file = "input.pl";
     3  open (FH, "<", $file) or die "Can't open $file: $!";
     4  while (<FH>) {
     5    push @line, $_;
     6  }
     7  close (FH) or die "Can't close $file: $!";
     8
     9  for ($i=0; $i<=$#line; $i++) {
    10    print "i = $i\n";
    11    $line[$i] = lc($line[$i]);
    12    $line[$i] =~ s/\W/ /g;
    13    $line[$i] =~ s/\b[^ \t]\b//g;
    14    $line[$i] =~ s/[^a-z\n ]//g;
    15    print $line[$i],"\n";
    16  }
    17
$
$ # Perl program execution
$ perl process.pl
i = 0
   usr bin perl
i = 1
i = 2
use strict
i = 3
i = 4
  this line will print  hello world line
i = 5
print  hello world
i = 6
i = 7
exit
$
$

if ( ! $_ =~ m/^\s*$/)
         {
            printf ("%${currLongest}s: %4d times, lines: %0s\n", $_, $occurCount{$_}, $lineConcat{$_});
         }

$
$ # The data file
$ cat -n input.pl
     1  #!/usr/bin/perl -w
     2
     3  use strict;
     4
     5  # This line will print a hello world line.
     6  print "Hello world!\n";
     7
     8  exit 0;
$
$ # The Perl program
$ cat -n process1.pl
     1  #!perl -w
     2  use strict;
     3
     4  my @line;
     5  my %words;
     6
     7  # Store the file contents in an array
     8  my $file = $ARGV[0];
     9  open (FH, "<", $file) or die "Can't open $file: $!";
    10  while (<FH>) {
    11    push @line, $_;
    12  }
    13  close (FH) or die "Can't close $file: $!";
    14
    15  for (my $i=0; $i<=$#line; $i++) {
    16    $line[$i] = lc($line[$i]);
    17    $line[$i] =~ s/\W/ /g;
    18    $line[$i] =~ s/\b[^ \t]\b//g;
    19    $line[$i] =~ s/[^a-z\n ]//g;
    20
    21    # Create a hash called "words", each key of which is a word.
    22    # The value is an arrayref, the first element of which is the word count
    23    # and the remaining elements are the line numbers where the words occur.
    24    foreach my $j (split/[ ]+/, $line[$i]) {
    25      if ($j ne "") {
    26        # increment the word count
    27        $words{$j}->[0]++;
    28        # ensure that the line numbers are unique
    29        if ($#{$words{$j}} == 0 or ($i+1) != $words{$j}->[$#{$words{$j}}]) {
    30          push @{$words{$j}}, ($i+1);
    31        }
    32      }
    33    }
    34  }
    35
    36  # finally, simply the print the hash in desired format
    37  foreach my $k (sort keys %words) {
    38    my $count = shift @{$words{$k}};
    39    printf ("%10s: %5d times, lines: %s\n", $k, $count, join(",", @{$words{$k}}));
    40  }
    41
$
$
$ # The execution of the Perl program
$ perl process1.pl input.pl
       bin:     1 times, lines: 1
      exit:     1 times, lines: 8
     hello:     2 times, lines: 5,6
      line:     2 times, lines: 5
      perl:     1 times, lines: 1
     print:     2 times, lines: 5,6
    strict:     1 times, lines: 3
      this:     1 times, lines: 5
       use:     1 times, lines: 3
       usr:     1 times, lines: 1
      will:     1 times, lines: 5
     world:     2 times, lines: 5,6
$
$