I wanted to use GNU parallel tool to make rsync file transfer to several hosts faster, but it seems that the parallel tool doesn't make it parallel much.
I expected time parallel "sleep 5; echo {}" ::: 1 2 3
to take not much longer than 5 seconds, but in real, it is:
real 0m16.306s
user 0m0.275s
sys 0m0.108s
which seems to be the same as for i in 1 2 3; sleep 5; done
i.e. not parallelized at all. What do I do wrong?