$ perl -le '
> @arr = qw{one two three};
> print qq{@arr};
> push @arr, q{four};
> print qq{@arr};'
one two three
one two three four
$

##</code><code>##

$ perl -le '
> $str = q{abcde};
> print $str;
> $str .= q{fgh};
> print $str;'
abcde
abcdefgh
$