$ time shuf -i 1-4294967296 -n 10000000 | sort | uniq - sorted1.txt

real    0m21.387s
user    0m22.700s
sys     0m0.820s
$ time shuf -i 1-4294967296 -n 10000000 | sort | uniq - sorted2.txt

real    0m21.230s
user    0m22.417s
sys     0m0.703s
$ time comm -1 -2 sorted1.txt sorted2.txt > results.txt

real    0m2.697s
user    0m2.643s
sys     0m0.053s
$ wc -l results.txt
23129 results.txt