Do you want to use a perl variable as if it were a file? Previous versions of perl had IO::Stringy and IO::Scalar for that. Perl 5.8 with PerlIO has it natively. Just use a reference to the scalar in the filename slot of open.

my $foo = '';
open FILEHANDLE, '+>', \$foo or die $!;
print FILEHANDLE "Contents of File";
seek(FILEHANDLE,0,0);
my @contents = <FILEHANDLE>;
close FILEHANDLE or die $!;
print 'From $foo: ', $foo, $/;
print 'From file read: ', @contents, $/;
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I meditated on this in Open Has a New Trick.

After Compline,
Zaxo