That's not an initialization - that's keeping the FILE I'm working with from affecting any other FILE filehandles in the program. For example:

use Fatal qw( open ); # Because I'm lazy

open FILE, "one";
print scalar(<FILE>);
{
   local *FILE;
   open FILE, "two";
   print <FILE>;
   close FILE;
}
print <FILE>;
close FILE;
[download]

That will print out the first line of one, then all of two, and then the rest of one.

Note: A lot more explanation of this same usage can be found by checking out local.

His Royal Cheeziness

If you're writing a simple script, there's little reason to do this yourself. If you're writing a module, the better thing to do now is use IO::File for file access.

Additionally it has another effect: when you leave that scope the filehandle is closed automagically:

use warnings;
{
   local *T;
   open(T, ">foo") || die;
   print T "HALHGLAG\n";  # Works okay!
}
print T "Surprise!\n";  # warns "print() on closed file..."
[download]

That is code like

local *FILE;
open FILE, $filename or die "Can't open file: $!";
my $data = <FILE>;
close FILE;
[download]

open my $file, $filename or die "Can't open file: $!";
my $data = <$file>;
close $file;
[download]

--
Ilya Martynov (http://martynov.org/)

As stated in perlstyle, it is very important that the debugging message includes all of the important information, including the filename. (And for those who think I sound like a broken record on this, spend a couple of hours late at night trying to figure out which file out of several thousand accessed by a script you have never seen broke the production run, and then tell me that insisting on having the filename is unreasonable...)

A few incidental points. The first is that people seeking to slurp a file usually don't want just the first line. And secondly if you make a habit of scoping file handles tightly, there is no need to close them. Your preferences may vary, but I usually don't bother. And finally, as chip says, if you have the choice in 5.6.0+, it is better to use the 3-arg open. See Two-arg open() considered dangerous for details and discussion.

sub slurp_file {
  my $file_name = shift;
  open(my $fh, "<", $file_name) or confess("Cannot read '$file_name': 
+$!");
  wantarray ? <$fh> : join '', <$fh>;
}
[download]

A very hearty thanks to everyone who posted a response to my query. All were very informative!