There are no built-in length restrictions on Perl's strings; in practice, the limitation is how much of your system's memory is available to Perl (this is something your system administrator can set, so check local listings).

The most efficient ways of reading a whole file into a scalar involve unsetting the input record separator $/ and then reading in the file (by unsetting the separator, nothing counts as a break between lines, so to speak). A bit of code that does that is:

my $str;
{
    local $/; # sets $/ to undef only WITHIN the braces
    open FILE, $filename or die "Can't open $filename: $!\n";
    $str = <FILE>;
    close FILE:
}
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HTH.

perl -e 'print "How sweet does a rose smell? "; chomp ($n = <STDIN>); 
+$rose = "smells sweet to degree $n"; *other_name = *rose; print "$oth
+er_name\n"'
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