I can tell you that you should use:

• strict
• -w
• $output

when using strict, and -w ${'output'} results in:

Can't use string ("output") as a SCALAR ref while "strict refs" in use at ./lal line 8.

When you use ${'output'} you are trying to dereference 'output'...
To be more exact: using $output means using whatever output contains.
using ${'output'} means using whatever 'output' points to, since it is highly
unlikely that 'output' is/will ever become a valid reference, this results in an
error (caught by 'use strict')

GreetZ!,

ChOas

print "profeth still\n" if /bird|devil/;