perl -wMstrict -le "my @arr1 = qw(one two three four five); my @arr2 = qw(one a b one c d e two f g h two i j two); my %seen1 = map { $_ => 0 } @arr1; @arr2 = grep { ! exists $seen1{$_} or ! $seen1{$_}++ } @arr2; print qq(@arr2); " one a b c d e two f g h i j