raspbian.pi

## 2017 Sept RPi 3
serial gpio to USB requires editing `config.txt` on sdcard, see the following
http://elinux.org/RPi_Serial_Connection
https://raspberrypi.stackexchange.com/questions/44427/how-to-connect-a-raspberry-pi-3-to-usb-tty-cable

## older, older models

https://www.raspberrypi.org/downloads/raspbian/
download the image then expand the archive and:
diskutil list
diskutil unmountDisk /dev/disk<disk# from diskutil>
sudo dd bs=1m if=2016-09-23-raspbian-jessie.img of=/dev/disk4
https://www.raspberrypi.org/documentation/installation/installing-images/mac.md
https://www.raspberrypi.org/documentation/remote-access/web-server/nginx.md

nmap -sP 192.168.0.*
https://www.raspberrypi.org/documentation/remote-access/ssh/unix.md

http://raspberrypi.stackexchange.com/questions/34330/raspbian-without-a-gui-and-other-programs-i-dont-need
http://raspberrypi.stackexchange.com/questions/5258/how-can-i-remove-the-gui-from-raspbian-debian
sudo apt-get remove --auto-remove --purge wolfram-engine scratch sonic-pi idle3 smartsim penguinspuzzle java-common minecraft-pi raspberrypi-artwork python3-numpy python3-rpi.gpio python-serial python3-serial python3-picamera debian-reference-en python3-pifacecommon python3-pifacedigitalio python3-pifacedigital-scratch-handler python-pifacecommon python-pifacedigitalio libx11-6 menu-xdg gstreamer1.0-omx gstreamer1.0-plugins-base gstreamer1.0-libav alsa-utils netsurf-gtk omxplayer cups* gnome* x11-common* autoremove

https://www.raspberrypi.org/documentation/raspbian/updating.md
http://raspberrypi.stackexchange.com/questions/164/how-do-i-update-software-and-firmware
sudo apt-get update
# user-space
sudo apt-get upgrade -y
# or
sudo apt-get dist-upgrade -y && sudo apt-get autoremove && sudo apt-get autoclean

http://raspberrypi.stackexchange.com/questions/164/how-do-i-update-software-and-firmware
https://help.ubuntu.com/lts/serverguide/automatic-updates.html


https://www.raspberrypi.org/documentation/linux/usage/users.md


# backup
diskutil list
sudo dd if=/dev/disk1 of=~/raspberrypi-backup.img
# NOTE r in rdisk
sudo diskutil eject /dev/rdisk1

# restore
diskutil list
=> identify disk, eg /dev/disk1
diskutil unmountDisk /dev/disk1
# NOTE disk1 prefix r for rdisk1 (raw disk)
sudo dd bs=1m if=~/raspberrypi-backup.img of=/dev/rdisk1
# for error "dd: invalid number '1m'" adjust 1m to 1M
# NOTE monitor progress via Ctrl+T for SIGINFO
sudo diskutil eject /dev/rdisk1
# see also https://www.raspberrypi.org/documentation/installation/installing-images/mac.md
# fix free space (http://raspberrypi.stackexchange.com/questions/499/how-can-i-resize-my-root-partition)
sudo raspi-config