$/ = "\r\n\r\n";
open( UIEEFILE, '<', '/path/to/file.txt' );
while (<UIEEFILE>) {
    my %book = ();
    foreach my $line ( split( "\r\n", $_ ) ) {
        my ( $key, $value ) = split( /\|/, $line, 2 );
        if ( defined( $book{$key} ) ) {
            $book{$key} .= " $value";
        }
        else {
            $book{$key} = $value;
        }
        # do something with %book
    }
}