Shell Programming and Scripting

       GNU parallel is a shell tool for executing jobs in parallel using one
       or more computers. A job is can be 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. A job can also be a command that reads from
       a pipe. GNU parallel can then split the input and pipe it into commands
       in parallel.

       If you use xargs and tee 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.

       pdsh is a variant of the rsh(1) command. Unlike rsh(1), which runs
       commands on a single remote host, pdsh can run multiple remote commands
       in parallel. pdsh uses a "sliding window" (or fanout) of threads to
       conserve resources on the initiating host while allowing some
       connections to time out.