Difference between "perl" and "perl -w"?

Question

I am learning Perl , very new user . May i know whats the difference between these Perl codes.

#!/usr/bin/perl

&

#!/usr/bin/perl -w

Answer 1

That is not perl code, it's a shebang, which is used in a linux/unix environment as a way to tell the shell what program should be used to run the program file. It has no effect in windows, but it does activate any switches used.

The -w part is a switch for perl, telling it to activate warnings. You can learn more about perl's command line switches by typing perl -h at the command prompt. Read more in perldoc perlrun

-w is the older version of the use warnings pragma, which is preferred nowadays. While -w is global, use warnings is lexical, and can be activated selectively.