#!/usr/bin/env perl

use strict;
use warnings;
use autodie;

my %wanted_records = map { $_ => 1 } @ARGV;

my $filename = 'pm_1203774_transient_data';

check_temporary_file($filename);
create_temporary_file($filename);
check_temporary_file($filename);
process_temporary_file($filename, \%wanted_records);
check_temporary_file($filename);
delete_temporary_file($filename);
check_temporary_file($filename);

sub create_temporary_file {
    my ($file_to_create) = @_;

    open my $out_fh, '>', $file_to_create;

    print $out_fh "$_\n" for 'A' .. 'Z';

    return;
}

sub process_temporary_file {
    my ($file_to_process, $wanted_records_ref) = @_;

    my $total_records = 0;

    {
        open my $in_fh, '<', $file_to_process;

        while (<$in_fh>) {
            next unless delete $wanted_records_ref->{$.};

            print "Record $.: $_";
        }

        $total_records = $.;
    }

    print "No. of records: $total_records\n";

    my @problem_records = sort keys %$wanted_records_ref;

    if (@problem_records) {
        warn "Problem records: @problem_records\n";
    }

    return;
}

sub delete_temporary_file {
    my ($file_to_delete) = @_;

    unlink $file_to_delete;

    return;
} 

sub check_temporary_file {
    my ($file_to_check) = @_;

    if (-e $file_to_check) {
        print "'$file_to_check' exists.\n";
    }
    else {
        print "'$file_to_check' not found.\n";
    }

    return;
}

##</code><code>##

$ pm_1203774_file_io_basics.pl
'pm_1203774_transient_data' not found.
'pm_1203774_transient_data' exists.
No. of records: 26
'pm_1203774_transient_data' exists.
'pm_1203774_transient_data' not found.

##</code><code>##

$ pm_1203774_file_io_basics.pl 1 2 3
'pm_1203774_transient_data' not found.
'pm_1203774_transient_data' exists.
Record 1: A
Record 2: B
Record 3: C
No. of records: 26
'pm_1203774_transient_data' exists.
'pm_1203774_transient_data' not found.

##</code><code>##

$ pm_1203774_file_io_basics.pl 26 24 25
'pm_1203774_transient_data' not found.
'pm_1203774_transient_data' exists.
Record 24: X
Record 25: Y
Record 26: Z
No. of records: 26
'pm_1203774_transient_data' exists.
'pm_1203774_transient_data' not found.

##</code><code>##

$ pm_1203774_file_io_basics.pl A B C 26 1 27 0 2 garbage
'pm_1203774_transient_data' not found.
'pm_1203774_transient_data' exists.
Record 1: A
Record 2: B
Record 26: Z
No. of records: 26
Problem records: 0 27 A B C garbage
'pm_1203774_transient_data' exists.
'pm_1203774_transient_data' not found.

##</code><code>##

#!/usr/bin/env perl

use strict;
use warnings;
use autodie;

my $filename = 'pm_1203774_sample.ged';

{
    my $start_char = '0';
    local $/ = "\n$start_char";

    open my $fh, '<', $filename;

    while (<$fh>) {
        chomp;
        $_ = $start_char . $_ unless $. == 1;
        $_ .= "\n" unless eof;
        print "Record #$.\n";
        print;
    }
}

##</code><code>##

Record #1
0 HEAD
1 SOUR PAF
2 NAME Personal Ancestral File
2 VERS 5.0
1 DATE 30 NOV 2000
1 GEDC
2 VERS 5.5
2 FORM LINEAGE-LINKED
1 CHAR ANSEL
1 SUBM @U1@
Record #2
0 @I1@ INDI
1 NAME John /Smith/
1 SEX M
1 FAMS @F1@
Record #3
0 @I2@ INDI
1 NAME Elizabeth /Stansfield/
1 SEX F
1 FAMS @F1@
Record #4
0 @I3@ INDI
1 NAME James /Smith/
1 SEX M
1 FAMC @F1@
Record #5
0 @F1@ FAM
1 HUSB @I1@
1 WIFE @I2@
1 MARR
1 CHIL @I3@
Record #6
0 @U1@ SUBM
1 NAME Submitter
Record #7
0 TRLR