...
{
    local $/ = \1173;
    ...
}
...

##</code><code>##

...
my $inputFile = q{C:/INPUTFILE};
open my $inputFH, q{<}, $inputFile
   or die qq{open: < $inputFile: $!\n};

my $outputFile = q{C:/OUTPUT.TXT};
open my $outputFH, q{>}, $outputFile
   or die qq{open: > $outputFile: $!\n};
...
    while( <$inputFH> )
...
    print $outputFH ...
...
close $inputFH or die qq{close: < $inputFile: $!\n};
close $outputFH or die qq{close: > $outputFile: $!\n};

##</code><code>##

...
my $rcount;
{
    local $/ = \1173;
    my $discard = <$inputFH> for 1 .. 7;
    $rcount = 7;  # We've seen and skipped 7 records so far.
    while( <$inputFH> )
    {
        $rcount ++;
        my @fields = unpack q{A34 ... }, $_;
        ...
    }
}
...
# Do something with $rcount here?
...