UNIX for Advanced & Expert Users

#!/usr/local/bin/perl

use strict;
use warnings;

my $input='input.file';
my @arr1;
my @arr2;

open(IN,$input) or die "Error opening input file $input: $!\n";
my @arr=<IN>;
close(IN);

foreach (@arr) {   
chomp;
push @arr1, $_ if $_ =~ /[0-9]/;
push @arr2, $_ if $_ =~ /[a-z]/;
}

print "$arr1[0]. $arr2[0]\n";
print "$arr1[1]. $arr2[1]\n";
print "$arr1[2]. $arr2[2]\n";

perl -ne 'if ( /(^\d+$)/ ) { $h{++$i} = $1 . ". " }; if ( /(^[a-z]+)$/ ) { $h{$j} = $h{++$j} . $1 }; eof && print map "$h{$_}\n", sort keys %h' data

perl -nle 'if (/^\d+/) { push @nums, $_; } else { push @oth,  $_; } END { for $i (0..($#nums<=$#oth ? $#nums : $#oth)) { print "$nums[$i].$oth[$i]"; } }' data

perl -ne 'if ( /(^\d+$)/ ) { $h{++$i} = $1 . ". " }; if ( /(^[a-z]+)$/ ) { $h{$j} = $h{++$j} . $1 }; END { print map "$h{$_}\n", sort { $a <=> $b } keys %h }' data