Use Perl use vars Pragma

Vars in Perl is a pragma (precompiled indicator) in Perl that is used to predefine global variables. These predefined global variables are in the QW () list, it can be used in the entire referenced perl file. Even if you use strict, no error is reported:

Use strict;

$ STR = "Hello world! \ N ";

Error message: global symbol "$ Str" requires explicit package name ~ Vars. pl line 3.
Execution ~ Vars. pl aborted dueComplication errors.

Execute the result after referencing use vars:

Use strict;

Use vars QW ($ Str );

$ STR = "Hello world! \ N ";

Print $ STR;

Output:

Hello world!