>perl -Mstrict -w -M-warnings=uninitialized -E 'my @a=(1..5,undef,6..10); say "@a" while defined shift @a'
2 3 4 5  6 7 8 9 10
3 4 5  6 7 8 9 10
4 5  6 7 8 9 10
5  6 7 8 9 10
 6 7 8 9 10

>