build and execute command lines from standard input in parallel

 GNU Parallel is a shell tool for executing jobs in parallel using one
 or more 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, or
 a list of tables.
 .
 If you use xargs today you will find GNU Parallel very easy to use. 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 jobs in
 parallel. If you use ppss or pexec you will find GNU Parallel will
 often make the command easier to read.
 .
 GNU Parallel also makes sure output from the commands is the same
 output as you would get had you run the commands sequentially. This
 makes it possible to use output from GNU Parallel as input for other
 programs.