In addition to simply running jobs in the background:
mpsh$ command args &
mpsh allows a number of options to background jobs, specified after the ampersand.
Any letter will be assumed to be a job handler (see job handler section):
mpsh$ command args &x
A number, star, or exclamation point specify a multi-process job (see multi-process job section):
mpsh$ command args &4
Minus signs causes a job to run at lower priority. Multiple minuses increase the "niceness" level. The actual value is controlled by the mpsh-nice environment variable.
mpsh$ command args &--
All of these options can be combined.