The command **xargs** is present by default on most linux systems. It has the option flag -P for running commands in parallel.
$ cat /tmp/a.txt
sleep 2
sleep 2
sleep 2
sleep 2
$ time cat /tmp/a.txt | xargs -i /bin/sh -c {}
real 0m8.008s
user 0m0.000s
sys 0m0.004s
$ time cat /tmp/a.txt | xargs -P...
