Newbie question: I am very new to Perl and am a little confused about grep here.

my ($index) = grep $array[$_] eq $search_for, 0 .. $#array;

This is what I think is happening: grep is stepping through the range of numbers in list 0..$#array and substituting each in $_, and then using this as an index to find the corresponding element in @array. Eventually the expression $array[$_]eq $search_for is true and that element of the range 0..$#array is put into a list returned by grep, which is then assigned to ($index).

This is my area of confusion: If @array has duplicate values, why does grep seem to stop when it finds the first value rather than produce a list of two values? Yet if I replace ($list) with @list, I get the index of both duplicate elements. I would greatly appreciate it if someone could cast some light on my darkness here :)