my $value = (if condition?  then this: else this);


##</code><code>##

if($some_var eq 'X')
{
    $this_var = 'Run using X format';
}
else
{
    $this_var = 'Run using standard format';
}

##</code><code>##

$this_var = ($some_var eq 'X'? 'Run using X format':'Run using standard format');