Try perldoc -f shift, or shift:

If ARRAY is omitted, shifts the @_ array within the lexical scope of subroutines and formats

perlvar tells you what @_ is:

Within a subroutine the array @_ contains the parameters passed to that subroutine.

I also think that all the perl introductions I've read explain this.

Perl 6 - second systems done right

In reply to Re: trouble understanding code, and shift() w.o args by moritz
in thread trouble understanding code, and shift() w.o args by DanielM0412

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