Consider this

#!/usr/bin/perl -w
use strict;

( $2, $66 ) = ( 1, 2 );
__END__
Modification of a read-only value attempted at - line 4.
[download]

Then read `perldoc perlvar' and `perldoc perlre' to see why $N is special.

Also, error checking++ open FOO, $bar or die "whooops $!";

Also, you may wish to use diagnostics as it gives more wordy error messages, like:

Modification of a read-only value attempted at - line 4 (#1)
    (F) You tried, directly or indirectly, to change the value of a
    constant.  You didn't, of course, try "2 = 1", because the compile
+r
    catches that.  But an easy way to do the same thing is:

        sub mod { $_[0] = 1 }
        mod(2);

    Another way is to assign to a substr() that's off the end of the s
+tring.

    Yet another way is to assign to a foreach loop VAR when VAR
    is aliased to a constant in the look LIST:

            $x = 1;
            foreach my $n ($x, 2) {
                $n *= 2; # modifies the $x, but fails on attempt to mo
+dify the 2
            }

Uncaught exception from user code:
        Modification of a read-only value attempted at - line 4.
[download]

MJD says "you can't just make shit up and expect the computer to know what you mean, retardo!"

I run a Win32 PPM repository for perl 5.6.x and 5.8.x -- I take requests (README).

** The third rule of perl club is a statement of fact: pod is sexy.