C:\>perl -Mwarnings -e"$cookie = 6;"
Name "main::cookie" used only once: possible typo at -e line 1.

C:\>perl -Mwarnings -Mstrict -e"$cookie = 6;"
Global symbol "$cookie" requires explicit package name at -e line 1.
Execution of -e aborted due to compilation errors.

C:\>perl -Mwarnings -Mdiagnostics -e"$cookie = 6;"
Name "main::cookie" used only once: possible typo at -e line 1 (#1)
    (W once) Typographical errors often show up as unique variable names.
    If you had a good reason for having a unique name, then just mention it
    again somehow to suppress the message.  The our declaration is
    provided for this purpose.

    NOTE: This warning detects symbols that have been used only once so $c, @c,
    %c, *c, &c, sub c{}, c(), and c (the filehandle or format) are considered
    the same; if a program uses $c only once but also uses any of the others it
    will not trigger this warning.


C:\>perl -Mwarnings -Mstrict -Mdiagnostics -e"$cookie = 6;"
Global symbol "$cookie" requires explicit package name at -e line 1.
Execution of -e aborted due to compilation errors (#1)
    (F) You've said "use strict vars", which indicates that all variables
    must either be lexically scoped (using "my"), declared beforehand using
    "our", or explicitly qualified to say which package the global variable
    is in (using "::").

Uncaught exception from user code:
        Global symbol "$cookie" requires explicit package name at -e line 1.
Execution of -e aborted due to compilation errors.
 at -e line 1

C:\>