Hello rich.wilder,

If you’d kept reading, you’d have come to the section “Filehandles” beginning on page 21. GRADES is a bareword (a string¹ not preceded by a sigil), here technically a typeglob used as a filehandle. Originally, this was the only way to name filehandles in Perl, but in modern Perl the preferred way is to use a lexical scalar variable:

open(my $grades, ...
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See, e.g., this reference.

Note that Perl still predefines some “special” bareword filehandles: STDIN, STDOUT, STDERR, ARGV. See perlopentut.

¹Update: I should have said, an unquoted sequence of non-whitespace characters.

Hope that helps,

rich.wilder welcome,

to open a file handle the lexical form explained above is, nowadays, a must. Perl is better when you choose the right idiom. In this case the idiom is:

       open my $file_handle, '>', '/path/file.ext' or die "Open failed
+: $!";
       # or to be clean put parens to open args
       open (my $file_handle, '>', '/path/file.ext') or die "Open fail
+ed: $!"
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For future reference and further reading you can visit Re: Why don't file handles have sigils? (*) where tye says that the sigil for global filehandles is * like it happens for globs.

L*

There are no rules, there are no thumbs..
Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.