When you run a program on the command line it automatically opens two channels for output. One is called Standard Output the other one is called Standard Error.
By default they are both connected to the terminal where you ran the program, but you can separate them and redirect them or hide them separately.
Travis-CI is a service that offers Continuous Integration on Linux to open source project hosted on GitHub free of charge.
Appveyor offers similar service on MS Windows.
There are a lot of cases when you'd want to have some code accessing a web site. It might be to automate some human interaction or it can be because you would like to talk to an API. Let's see a few simple examples in Perl 6.
httpbin.org is an excellent web site that allows us to try all kinds of web client code. We are going to use that in our examples.
When writing a program, one of the best ways to make it reusable is by accepting parameters on the command line.
For example if you are writing a program that needs to parse a log file, you might want to supply the name of the logfile on the command line.
If the application needs to send an e-mail report, it is more generic if the user can supply the address as a command line parameter: --to boss@company
How can you let your Perl 6 application accept command line arguments?