FAQ 8.26 Why doesn't open() return an error when a pipe open fails?
in [Perl]
|
Prev: FAQ 9.7 How do I make an HTML pop-up menu with Perl?
Next: FAQ 3.26 Where can I learn about object-oriented Perl programming?
From: PerlFAQ Server on 8 Aug 2010 06:00 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 . -------------------------------------------------------------------- 8.26: Why doesn't open() return an error when a pipe open fails? If the second argument to a piped "open()" contains shell metacharacters, perl "fork()"s, then "exec()"s a shell to decode the metacharacters and eventually run the desired program. If the program couldn't be run, it's the shell that gets the message, not Perl. All your Perl program can find out is whether the shell itself could be successfully started. You can still capture the shell's STDERR and check it for error messages. See "How can I capture STDERR from an external command?" elsewhere in this document, or use the "IPC::Open3" module. If there are no shell metacharacters in the argument of "open()", Perl runs the command directly, without using the shell, and can correctly report whether the command started. -------------------------------------------------------------------- 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. |