GNU parallel is a shell tool for executing jobs in parallel locally or
using remote machines. A job is typically a single command or a small
script that has to be run for each of the lines in the input. The
typical input is a list of files, a list of hosts, a list of users, a
list of URLs, or a list of tables.
If you use xargs today you will find GNU parallel very easy to use as
GNU parallel is written to have the same options as xargs. If you
write loops in shell, you will find GNU parallel may be able to
replace most of the loops and make them run faster by running several
jobs in parallel. If you use ppss or pexec you will find GNU parallel
will often make the command easier to read.