cat list1.txt list2.txt ... listN.txt |\
LC_ALL=C parsort --parallel=24 -k1 | /path/to/tally-count |\
LC_ALL=C parsort --parallel=24 -k2nr > out.txt

##</code><code>##

cat list1.txt list2.txt ... listN.txt |\
LC_ALL=C parsort --parallel=24 -T /path/to/tmpdir -k1 | /path/to/tally-count |\
LC_ALL=C parsort --parallel=24 -T /path/to/tmpdir -k2nr > final.txt

##</code><code>##

cat list1.txt list2.txt ... listN.txt |\
LC_ALL=C mcesort --parallel=24 -T /path/to/tmpdir -k1 | /path/to/tally-count |\
LC_ALL=C mcesort --parallel=24 -T /path/to/tmpdir -k2nr > final.txt

##</code><code>##

cat list1.txt list2.txt ... listN.txt |\
mcesort -A -j24 -T /path/to/tmpdir --tally=/path/to/tally-count -k1 |\
mcesort -A -j24 -T /path/to/tmpdir -k2nr > final.txt

##</code><code>##

NUM_THREADS=24 llil4map list1.txt list2.txt ... listN.txt > final.txt
NUM_THREADS=24 llil4hmap list1.txt list2.txt ... listN.txt > final.txt
NUM_THREADS=24 llil4emh list1.txt list2.txt ... listN.txt > final.txt

##</code><code>##

NUM_THREADS=24 llil4vec list1.txt list2.txt ... listN.txt > final.txt