https://www.gnu.org/software/parallel/parallel_tutorial.html
https://stackoverflow.com/questions/28357997/running-programs-in-parallel-using-xargs

books
Ole Tange - GNU Parallel 2018

samples

# a list of A B C
parallel echo ::: A B C
parallel echo {} ::: A B C
parallel -a abc-file echo
cat abc-file | parallel echo

# cartesian product
parallel echo ::: A B C ::: def     
parallel -a abc-file -a def-file echo
parallel -a abc-file :::: def-file echo

# A D
# B E
# C F
# in other words - zip
parallel --link echo ::: A B C ::: D E F     
parallel --link echo ::: A B C D E ::: F G     
# see also :::+ ::::+

# ranges
parallel echo ::: {1..3}

# inserts none for the the arg
parallel -N0 echo this {} ::: {1..3} 
parallel -N0 echo this ::: {1..3} 

# skips entire ...
parallel 'echo this is {=skip()=}' ::: {1..3} 

time parallel -j 4 -N0 curl -s "http://localhost:8080/analyze?text=Some+text" > /dev/null ::: {1..1000}