screenblank —
screen saver daemon for wscons and FBIO machines
  
    | screenblank | [ -k|-m]
      [-dinactivity-timeout]
      [-ewakeup-delay]
      [-fframebuffer]
      [-iinput-device] | 
screenblank disables the framebuffer if the keyboard and
  mouse are idle for a period of time, and re-enables the framebuffer when
  keyboard or mouse activity resumes.
When killed with a SIGINT, SIGHUP, or SIGTERM,
    screenblank will re-enable the framebuffer. The pid
    can be found in the file
  /var/run/screenblank.pid.
The options are as follows:
  - -b
- Overriding the other options, simply try (once) to blank the framebuffer,
      then exit.
- -dinactivity-timeout
- Wait the number of seconds specified by
      inactivity-timeout, expressed in the format
      “xxx.xxx”, before disabling the framebuffer due to
      inactivity. The default is 600 seconds (10 minutes).
- -ewakeup-delay
- Wait the number of seconds specified by
      wakeup-delay, expressed in the format
      “xxx.xxx”, before re-enabling the framebuffer once activity
      resumes. The default is .25 seconds.
- -fframebuffer
- Use the framebuffer device framebuffer instead of
      the default /dev/fb.
- -iinput-device
- Add input-device to the list of devices to monitor
      for activity.
- -k
- Do not check the keyboard for activity.
- -m
- Do not check the mouse for activity.
- -u
- Overriding the other options, simply try (once) to unblank the
      framebuffer, then exit.
Note that the -k and
    -m flags are mutually exclusive.
  - /dev/kbd
- The keyboard device.
- /dev/mouse
- The mouse device.
- /dev/console
- The console device.
- /dev/fb
- The default framebuffer.
- /dev/wskbd
- The keyboard for wscons machines.
- /dev/wsmouse
- The mouse device for wscons machines.
- /dev/ttyE0
- The console device for wscons machines.
- /var/run/screenblank.pid
- File containing the pid of screenblank.
screenblank checks the access and modification times of
  the devices it is monitoring to determine activity. If the devices are on a
  file system mounted with the noatime and/or
  nodevmtime options, it will not function as expected.
  A possible workaround is to use a script as such:
#!/bin/sh
/usr/sbin/screenblank -d 0 -e 0 && read
/usr/bin/pkill screenblank