What does =~ do in Perl?

=~ is the operator testing a regular expression match. The expression /9eaf/ is a regular expression (the slashes // are delimiters, the 9eaf is the actual regular expression). In words, the test is saying “If the variable $tag matches the regular expression /9eaf/ …” and this match occurs if the string stored in $tag contains those characters 9eaf consecutively, in order, at any point. So this … Read more

“inappropriate ioctl for device”

Most likely it means that the open didn’t fail. When Perl opens a file, it checks whether or not the file is a TTY (so that it can answer the -T $fh filetest operator) by issuing the TCGETS ioctl against it. If the file is a regular file and not a tty, the ioctl fails and sets errno to ENOTTY (string value: … Read more

“inappropriate ioctl for device”

Most likely it means that the open didn’t fail. When Perl opens a file, it checks whether or not the file is a TTY (so that it can answer the -T $fh filetest operator) by issuing the TCGETS ioctl against it. If the file is a regular file and not a tty, the ioctl fails and sets errno to ENOTTY (string value: … Read more