FAQ 8.37 How do I find out if I'm running interactively or not?

P

PerlFAQ Server

This is an excerpt from the latest version perlfaq8.pod, which
comes with the standard Perl distribution. These postings aim to
reduce the number of repeated questions as well as allow the community
to review and update the answers. The latest version of the complete
perlfaq is at http://faq.perl.org .

--------------------------------------------------------------------

8.37: How do I find out if I'm running interactively or not?

(contributed by brian d foy)

This is a difficult question to answer, and the best answer is only a
guess.

What do you really want to know? If you merely want to know if one of
your filehandles is connected to a terminal, you can try the "-t" file
test:

if( -t STDOUT ) {
print "I'm connected to a terminal!\n";
}

However, you might be out of luck if you expect that means there is a
real person on the other side. With the "Expect" module, another program
can pretend to be a person. The program might even come close to passing
the Turing test.

The "IO::Interactive" module does the best it can to give you an answer.
Its "is_interactive" function returns an output filehandle; that
filehandle points to standard output if the module thinks the session is
interactive. Otherwise, the filehandle is a null handle that simply
discards the output:

use IO::Interactive;

print { is_interactive } "I might go to standard output!\n";

This still doesn't guarantee that a real person is answering your
prompts or reading your output.

If you want to know how to handle automated testing for your
distribution, you can check the environment. The CPAN Testers, for
instance, set the value of "AUTOMATED_TESTING":

unless( $ENV{AUTOMATED_TESTING} ) {
print "Hello interactive tester!\n";
}



--------------------------------------------------------------------

The perlfaq-workers, a group of volunteers, maintain the perlfaq. They
are not necessarily experts in every domain where Perl might show up,
so please include as much information as possible and relevant in any
corrections. The perlfaq-workers also don't have access to every
operating system or platform, so please include relevant details for
corrections to examples that do not work on particular platforms.
Working code is greatly appreciated.

If you'd like to help maintain the perlfaq, see the details in
perlfaq.pod.
 

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments. After that, you can post your question and our members will help you out.

Ask a Question

Members online

No members online now.

Forum statistics

Threads
473,744
Messages
2,569,483
Members
44,903
Latest member
orderPeak8CBDGummies

Latest Threads

Top