Global symbol "$another_variable" requires explicit package name at diag.pl line 6. Execution of diag.pl aborted due to compilation errors (#1) (F) You've said "use strict" or "use strict vars", which indicates that all variables must either be lexically scoped (using "my" or "state"), declared beforehand using "our", or explicitly qualified to say which package the global variable is in (using "::"). Uncaught exception from user code: Global symbol "$another_variable" requires explicit package name at diag.pl line 6. Execution of diag.pl aborted due to compilation errors. at diag.pl line 6