while (
    ! $no_error_opening_file
    and !( eof and $need_not_process_beyond_eof )
    and ! $found_all_elements_I_was_looking_for 
) {

##</code><code>##

until( 
    $no_error_opening_file 
    or ( eof and $need_not_process_beyond_eof )
    or $found_all_elements_i_was_looking_for 
) {

##</code><code>##

open FH ... or die ...;
while( <FH> ) {
    my $foundEverything = processLine( $_ );
    last if $foundEverything;   
}

##</code><code>##

open FH ... or die ..;
until( eof FH ) {
    my $line1 = <FH>;
    my $line2 = <FH>;
    my $foundEverything = processRecord( $line1, $line2 );
    last if $foundEverything;
}