Harry Putnam <[email protected]> asked:
> I see advanced users here using various styles of open().
[three argument open]
> Is there something beyond style that makes those methods better than
> what appears to be a simpler format:
[two argument open]
Allow me to quote "perldoc -f open":
The filename passed to 2-argument (or 1-argument) form of open()
will have leading and trailing whitespace deleted, and the normal redirection
characters honored. This property, known as "magic open", can often be used to
good effect. A user could specify a filename of "rsh cat file |", or you could
change certain filenames as needed:
$filename =~ s/(.*\.gz)\s*$/gzip -dc < $1|/;
open(FH, $filename) or die "Can't open $filename: $!";
Use 3-argument form to open a file with arbitrary weird
characters in it,
open(FOO, '<', $file);
otherwise it's necessary to protect any leading and trailing
whitespace:
$file =~ s#^(\s)#./$1#;
open(FOO, "< $file\0");
(this may not work on some bizarre filesystems). One should
conscientiously choose between the magic and 3-arguments form of open():
open IN, $ARGV[0];
will allow the user to specify an argument of the form "rsh cat
file |", but will not work on a filename which happens to have a trailing
space, while
open IN, '<', $ARGV[0];
will have exactly the opposite restrictions.
I hope this answers your question ;-)
Cheers,
Thomas
--
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
http://learn.perl.org/
