Question

I feel stupid for asking this, but I’ve tried a couple things and I’m not sure where to go with it.

From the Expect.pm documentation:

$object->log_file("filename" | $filehandle | \&coderef | undef)

Log session to a file. All characters send to or received from
the spawned process are written to the file.

I’d like to pass the $filehandle to log_file. However, when I tried this:

open (LOG, ">>" .$opt{l});
my $sess = Expect->spawn("telnet $ip");
$sess->log_file(LOG)

I get a file named ‘LOG’ in the directory that I’m running the script out of. After some investigation, I tried this:

open (LOG, ">>" .$opt{l});
my $sess = Expect->spawn("telnet $ip");
my $fh = *LOG;
$sess->log_file($fh)

Now, I get a file named *main::LOG in the directory. I do have another file as well, named whatever I specified on the -l option, but it only contains the lines that I send to print LOG.

I’m not sure if the filehandling functionality is hosed in the function, or if I’m doing something wrong.

Answer 1

If you have a bareword filehandle named LOG, you can pass it to a function by saying \*LOG (you can read more about this in perldoc perldata), but don’t do that. Bareword filehandles are a very old style and should no longer be used. Try using a lexical filehandle and the three argument version of open:

open my $log, ">>", $opt{l}
    or die "could not open $opt{l}: $!";

you can use $log anywhere you used LOG in the past.

You should also be using the strict and warnings pragmas.