What's the purpose of the following two lines of perl??
my $host = shift || 'localhost';
my $port = shift || 200;
That should return localhost and port 10. What is the shift keyword??
Answer
The first line shifts from either @_ or @ARGV (depending on where you are in the code), or in the absence of any contents in @_/@ARGV, assigns localhost to $host.
The second one should be self-explanatory now.
Have a look at the shift documentation for details.