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my $host;
if ($host eq '') { shift } else { print("--\n"); }

Quote

shift ARRAY
shift Shifts the first value of the array off and returns it,
shortening the array by 1 and moving everything down. If there
are no elements in the array, returns the undefined value. If
ARRAY is omitted, shifts the @_ array within the lexical scope
of subroutines and formats, and the @ARGV array at file scopes
or within the lexical scopes established by the "eval ''",