Saturday, December 15, 2012

Bootstrap your Raspberry Pi with a Bash Script

I love my raspberry pi. I use it for fun projects. It's inexpensive, easy to use, and fun! Coincidentally, it also makes an easy dev environment for small projects.

I like to treat mine as a disposable test bed for different things I'm working on. I find myself doing repetitive configuration changes to the pi, so I've instead decided to script all the initial installation stuff.

Here's my setup script for all to use and enjoy. After my raspberry pi finishes it's general config screen, bootstrapping it is very easy (and interactive). If you have any comments, feel free to post them on Git or right here on the blog.

You can see the raw or full mode on github here.

If you'd like to run it and test it yourself, just run from root:

$ curl -q "https://raw.github.com/stephendotexe/raspberrypi/master/configuration/setup_pi_interactive" > ~/setup_pi_interactive 

(open up the file -- never run anything from the web as root without first looking it over)

$ ~/setup_pi_interactive


Let's break it down:

#!/bin/bash

# Interactive Raspberry Pi setup script
# Author: Stephen Wood (www.heystephenwood.com)

# Die on any errors
set -e 

if [[ `whoami` != "root" ]]
then
  echo "Script must be run as root."
  exit 1
fi

# Variables for the rest of the script
echo -n "Choose a hostname: "
read NEW_HOSTNAME
echo -n "User: "
read NEW_USER
echo -n "Password for user (leave blank for disabled): "
read PASS_PROMPT
echo -n "Paste public key (leave blank for disabled): "
read PUBLIC_KEY

I left this interactive for the sake of anyone else running the script. On my own personal version, I set this variables by hand and run it straight off, which is nice because you can do it in one line (curl "http://script" | bash), just make sure it's securely hosted locally if you are putting passwords in it.

apt-get -y update
apt-get -y upgrade

# Install some base packages
apt-get install -y --force-yes dnsutils g++ gcc ipython \
make ntp python python-pip vim vlc

Install whatever packages you want. I find this to be ones I like on every system.

# Update hostname
echo "$NEW_HOSTNAME" > /etc/hostname
sed -i 's/pi/$NEW_HOSTNAME/' /etc/hosts

# Set VIM as the default editor
update-alternatives --set editor /usr/bin/vim.basic

# Add user and authorized_keys
if [[ "$PASS_PROMPT" = "" ]]
then
  useradd -b /home --create-home -s /bin/bash -G sudo $NEW_USER
else
  useradd -b /home --create-home -s /bin/bash -G sudo $NEW_USER -p `echo "$PASS_PROMPT" | openssl passwd -1 -stdin` 
fi

Personally, I recommend you do SSH key-pairs for everything, but sometimes a password is just easier.

# Remove Pi user's password
passwd -d pi

The whole world knows the default password to this user, so disable the password or the user, your choice. I remove the password here. If you want to delete the user, you won't be able to do it with sudo on the first run.

if [[ "$PUBLIC_KEY" != "" ]]
then
  mkdir -p /home/$NEW_USER/.ssh/
  echo "$PUBLIC_KEY" > /home/$NEW_USER/.ssh/authorized_keys
fi
chown -R $NEW_USER:$NEW_USER /home/$NEW_USER

# Allow users in the sudo group to sudo without password
sed -i 's/%sudo.*/%sudo   ALL=NOPASSWD: ALL/g' /etc/sudoers

# Turn off password authentication 
sed -i 's/#   PasswordAuthentication yes/    PasswordAuthentication no/g' /etc/ssh/ssh_config

# Now for some memory tweaks!
# Remove unnecessary consoles
sed -ie 's|l4:4:wait:/etc/init.d/rc 4|#l4:4:wait:/etc/init.d/rc 4|g' /etc/inittab
sed -ie 's|l5:5:wait:/etc/init.d/rc 5|#l5:5:wait:/etc/init.d/rc 5|g' /etc/inittab
sed -ie 's|l6:6:wait:/etc/init.d/rc 6|#l6:6:wait:/etc/init.d/rc 6|g' /etc/inittab
# Also disable serial console
sed -ie 's|T0:23:respawn:/sbin/getty -L ttyAMA0 115200 vt100|#T0:23:respawn:/sbin/getty -L ttyAMA0 115200 vt100|g' /etc/inittab 

echo "Installation Complete. Some changes might require a reboot."

I got these tweaks from the blog Gordon @ Drogon.

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