#!/usr/bin/perl -w
use strict;
while(<DATA>)
{
    my $dot_ix = index $_ ,'.';

    printf "%40s: %s\n",
           "the string before trimming",
           $_;

    printf "%40s: %s\n",
           "dot+",
           substr $_, $dot_ix;

    printf "%40s: %s\n",
           "dot-2",
           substr($_, $dot_ix - 2);

    printf "%40s: %s\n",
           "trimmed fat",
           substr($_, $dot_ix - 2, $dot_ix -1, '');
           # $dot_ix -1 since it's the num of chars, not index

    printf "%40s: %s\n",
           "the string after trimming",
           $_;

}

__END__
1996.40637
1996.41064
1996.41199
1996.41467
1996.41882