while(my $pline=<PRFILE>) {
    chomp $pline;
    $parrecord = $pline;
    my @parfields = split();
    ...
}
##</code><code>##

CHILD: foreach (@carray) {
    # search <PRFILE> line-by-line for a match of $_ to field #5
    # if each field#5 in <PRFILE> is guaranteed unique, you can go to the next CHILD element once a match is found
}
##</code><code>##

my %lookupHash = ();
while(my $line=<CHFILE>) {
    chomp $line;
    my @fields = split(/\|/, $line);
    $lookupHash{ $fields[1] } = ();        # $field[1] = 2nd field
    #$lookupHash{ $fields[1] } = $line;    # need entire line?
}
##</code><code>##

while(my $line=<PRFILE>) {
    chomp $line;
    my @fields = split(/\|/, $line);
    print $OUTFILE $line."\n" if(exists $lookupHash{ $fields[4] });
}
##</code><code>##

field            pre  suf               $HoH{$pre}->{$suf} = ()
---------------- ---- ----------------- ------------------------
1400000042597061="1" +"400000042597061" $HoH{1}->{400000042597061}=();
                ="14"+"00000042597061"  $HoH{14}->{00000042597061}=();
                    ...

##</code><code>##

field            prefix       suffix   $HoH{$suf}->{$pre} = ();
---------------- -----------  -------- -------------------------
1400000042597061="1400000042"+"597061" $HoH{597061}->{1400000042}=();

##</code><code>##

my $prefix = substr($myField, 0, 11);
my $suffix = substr($myField, 11);

##</code><code>##

my %lookupHash = ();
LINE: while(my $line=<CHFILE>) {
    chomp $line;
    my @fields = split(/\|/, $line);
    my $prefix = substr($fields[1], 0, 11);  # Grab from pos0 to pos9
    my $suffix = substr($fields[1], 11);     # Grab from pos10 and on
    $lookupHash{$suffix}->{$prefix} = ();
    #$lookupHash{$suffix}->{$prefix} = $line;
}

##</code><code>##

LINE: while(my $line=<PRFILE>) {
    chomp $line;
    my @fields = split(/\|/, $line);
    
    # do suffix first; skip line in parent if suffix absent
    my $suffix = substr($fields[4], 11);
    next LINE if(!exists $lookupHash{$suffix});
    
    # reach here if suffix exists; check prefix
    my $prefix = substr($fields[4], 0, 11);
    next LINE if(!exists $lookupHash{$suffix}->{$prefix});
    
    # Output the parent line
    print $OUTFILE $line."\n";
    
    # ... or output the child line if you needed that one
    #print $OUTFILE $lookupHash{$suffix}->{$prefix}."\n";
}