You deserve a reference to read about those differences
From warnings:
The warnings pragma is a replacement for the command line flag -w , but the pragma is limited to the enclosing block, while the flag is global. See perllexwarn for more information.
Also: perllexwarn

In reply to Re^3: 'Invisible' newlines/line wrapping (-w) by toolic
in thread 'Invisible' newlines/line wrapping by luolimao

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