You can override builtin functions: http://docstore.mik.ua/orelly/perl/cookbook/ch12_12.htm and http://docstore.mik.ua/orelly/perl/prog/ch05_02.htm#PERL2-CH-5-SECT-2.2. Nothing difficult in making them conditional (call of the CORE:: version or printing depending on switch) and even caching (i.e. concatenating to a string that is eval'd eventually and that uses the CORE:: version of the function).

In reply to Re: File operations "preview" mode? by jethro
in thread File operations "preview" mode? by jh

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