#modern way
#
my $sortby = $cgi->param( 'sortby' ) // 'name';

# Perl5.8 way
#
my $sortby = $cgi->param( 'sortby' ) || 'name';

# If first value can be zero or empty string ..
#
my $sortby = ( defined $cgi->param( 'sortby' ) ? $cgi->param( 'sortby' )
             :                                   'name'
             );

# alternate arrangement
#
my $sortby = ( defined $cgi->param( 'sortby' ) 
             ? $cgi->param( 'sortby' )
             : 'name'
             );