echo sudo_o >&2
time tac <(seq 1 1000000) | awk 'a[$1]++{print $0 > "/dev/null";next}{print $0 > "/dev/null"}'
echo -e "\nkent" >&2
time awk '$1 in a{print a[$1]>"/dev/null"}{a[$1]=$0}END{for(x in a)print a[x]}' <(seq 1 1000000) > /dev/null
echo -e "\nscrutinizer" >&2
time awk 'NR==FNR{A[$1]=NR; next} A[$1]!=FNR{print>f; next}1' f=/dev/null <(seq 1 1000000) <(seq 1 1000000) > /dev/null
ZWNobyBzdWRvX28gPiYyCnRpbWUgdGFjIDwoc2VxIDEgMTAwMDAwMCkgfCBhd2sgJ2FbJDFdKyt7cHJpbnQgJDAgPiAiL2Rldi9udWxsIjtuZXh0fXtwcmludCAkMCA+ICIvZGV2L251bGwifScgCiAKZWNobyAtZSAiXG5rZW50IiA+JjIKdGltZSBhd2sgJyQxIGluIGF7cHJpbnQgYVskMV0+Ii9kZXYvbnVsbCJ9e2FbJDFdPSQwfUVORHtmb3IoeCBpbiBhKXByaW50IGFbeF19JyA8KHNlcSAxIDEwMDAwMDApID4gL2Rldi9udWxsCiAKIAplY2hvIC1lICJcbnNjcnV0aW5pemVyIiA+JjIKdGltZSBhd2sgJ05SPT1GTlJ7QVskMV09TlI7IG5leHR9IEFbJDFdIT1GTlJ7cHJpbnQ+ZjsgbmV4dH0xJyBmPS9kZXYvbnVsbCA8KHNlcSAxIDEwMDAwMDApIDwoc2VxIDEgMTAwMDAwMCkgPiAvZGV2L251bGw=