RAIN(6) BSD Games Manual RAIN(6)
rain -- animated raindrops display
rain [-d delay]
rain is modeled after the VAX/VMS program of the same name.
To obtain the proper effect, the -d option may be used to specify a delay
in milliseconds between each update. Reasonable values are around
20-200. The default is based on the terminal speed, computed via the
delay = speed / 9600 - 1
As with any curses(3) program, the TERM environment variable must be set
(and exported) to the type of the terminal being used.
Eric P. Scott
BSD January 15, 2015 BSD