Thanks Thomas. Appreciated.
Thomas Bätzler wrote:
Hi,
M. Lewis <[EMAIL PROTECTED]> asked:
Charles K. Clarkson recently replied to Sreedhar Reddy in
which one of the corrections he made was:
open my $fh, '<', $input_file or die qq(Cannot open
"$input_file": $!);
[...]
When I have opened a file, I have always done:
open (FILE, $file) || die "Cannot open $file :$!";
A couple of things different.
- I use a FILEHANDLE, where Charles used a variable.
Passing a filehandle to a subroutine is possible, but if
you use IO::Handle objects like Charles, it's much easier.
- Charles explicitly said the file was being opened for
reading. My understanding is that is the default. I assume
that Charles did this for clarity.
Security, too. In Charles' case, all the open ever does is
try to open a file. In your case, it could be used to do
almost anything. That's fine as long as your code runs on
your box only, probably with a fixed "my $file = ..."
right above it - but just imagine your code if part of a
CGI program and $file is a CGI parameter, and somebody
set it to '/bin/rm -rf /|'.
I rarely do CGI stuff so this really isn't really in my realm, although
I can see how via your example, it would be a good idea to make that a
habit.
- Charles opted to use qq() which cause him to have to
enclose the $input_file in "".
Dead wrong. He used qq() so that he did not have to quote
the "" inside a string which he wanted to be interpolated.
Delimiting arguments in an error message by quotes is
a very good idea because it lets you see leading or trailing
whitespace which you'd otherwise miss.
You've lost me here Thomas. Again, his code was:
open my $fh, '<', $input_file or die qq(Cannot open "$input_file": $!);
What am I missing here?
My question is, which way is better, and why is it better? My
assumption is Charles' method is better, but I would
appreciate knowing why.
HTH,
Thomas
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