Have you read the most basic documentation, perldoc perlsub?

And if that's insufficiently clear, try the subroutine section of Tutorials ...for the content itself, and for the experience of trying to answer your own questions.

In reply to Re^3: how to write a subroutine content into a file by ww
in thread how to write a subroutine content into a file by Pal-Cod3r

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