perl -MO=Deparse,-p -e 'print "$_\n" for < a >;'
[download]

use File::Glob ();
print("$_\n") foreach (glob(' a '));

perl -MO=Deparse,-p -e 'print "$_\n" for <a>;'
[download]

print("$_\n") foreach (readline(a));

From perlop (boldface added for emphasis):

If what's within the angle brackets is neither a filehandle nor a simple scalar variable containing a filehandle name, typeglob, or typeglob reference, it is interpreted as a filename pattern to be globbed, and either a list of filenames or the next filename in the list is returned, depending on context. This distinction is determined on syntactic grounds alone. That means <$x> is always a readline() from an indirect handle, but <$hash{key}> is always a glob(). That's because $x is a simple scalar variable, but $hash{key} is not--it's a hash element. Even <$x > (note the extra space) is treated as glob("$x "), not readline($x).

Hope that helps,

Athanasius <°(((>< contra mundum

סתם עוד האקר של פרל,

> Why are these different?

> perl -MO=Deparse,-p -e 'print "$_\n" for < a >;'

> perl -MO=Deparse,-p -e 'print "$_\n" for <a>;'

a could be an old-style bare-word file-handle, but " a " can't

think

• open a, "<", "filename"
instead of the common FH

one of the reasons why ppl are encouraged to use lexical filehandles:

• open my $fh, "<", "filename"

Cheers Rolf
_{(addicted to the 𐍀𐌴𐍂𐌻 Programming Language :)
Wikisyntax for the Monastery}

• update: added code tags in citations, thanks hippo++

From this StackOverflow answer,

• <> means readline(ARGV)
• <IDENTIFIER> means readline(IDENTIFIER)
• <$IDENTIFIER> means readline($IDENTIFIER)
• <...> (anything else) means glob(qq<...>)

<...> (anything else) means glob(qq<...>)
Anything? Except this:

perl -MO=Deparse,-p -e 'print "$_\n" for <<>>'
[download]

print("$_\n") foreach (<<>>);

Perl waits for input:

echo fubar | perl -e 'print "$_\n" for <<>>'
[download]

fubar