Programming Perl, 4th Edition

push

push ARRAY, LIST

This function treats ARRAY as a stack and pushes the values of LIST onto the end of ARRAY. The length of ARRAY increases by the length of LIST. The function returns this new length. The push function has the same effect as:

for my $value (listfunc()) {
    $array[++$#array] = $value;
}

or:

splice @array, @array, 0, listfunc();

but it is more efficient (for both you and your computer). You can use push in combination with shift to make a fairly time-efficient shift register or queue:

for (;;) {
    push @array, shift @array;
    ...
}

See also pop and unshift.

Starting with v5.14, push can take a reference to an unblessed array, which will be dereferenced automatically. This aspect of push is considered experimental. The exact behavior may change in a future version of Perl.