Raspberry Pi

Installing 2018-11-13-raspbian-stretch-full.img, I noticed the image performs more steps for the user, including...

• $ sudo apt-get update
• $ sudo apt-get upgrade

These commands prepare the unit for installation of new packages. Before installing packages, let's remove some packages that we will never use...

• $ sudo apt-get remove wolframscript
• $ sudo apt-get remove scratch
• $ sudo apt-get remove scratch2
• $ sudo apt-get remove nuscratch
• $ sudo apt-get remove sonic-pi
• $ sudo apt-get autoremove

Using the du command, I notice the image includes November 2018 issue of MagPi magazine

• $ rm -r ~/MagPi

$ df
 Filesystem     1K-blocks    Used Available Use% Mounted on
/dev/root       15203948 3335488  11185240  23% /
devtmpfs          470116       0    470116   0% /dev
tmpfs             474724       0    474724   0% /dev/shm
tmpfs             474724   18292    456432   4% /run
tmpfs               5120       4      5116   1% /run/lock
tmpfs             474724       0    474724   0% /sys/fs/cgroup
/dev/mmcblk0p1     44220   22540     21681  51% /boot
tmpfs              94944       0     94944   0% /run/user/1000

$ sudo hostname Porky

• Change Digital Clock settings - format from "%R" to "%I:%M%p" I don't like 24 hour mode, and I don't like seconds displayed.
• Edit ~/.bashrc, change one of the commented out alias to

alias ll='ls -la --color=auto'

pi@Porky:~ $ cat /proc/version
Linux version 4.14.79-v7+ (dc4@dc4-XPS13-9333) (gcc version 4.9.3 (crosstool-NG crosstool-ng-1.22.0-88-g8460611)) #1159 SMP Sun Nov 4 17:50:20 GMT 2018

Add apache2, enable cgi, configure permissions group for i2c

$ sudo apt-get install apache2
$ sudo a2enmod cgi
$ sudo service apache2 restart

Configure www-data as a member of group, i2c, such that it can use /dev/i2c-1

$ sudo usermod -aG i2c www-data   or use   $ sudo adduser www-data i2c

Copy cgi programs to /usr/lib/cgi-bin

$ sudo cp ~/projects/tempcgi/tempcgi.cgi /usr/lib/cgi-bin
$ sudo chmod 755 /usr/lib/cgi-bin/tempcgi.cgi
$ sudo chgrp www-data /usr/lib/cgi-bin/tempcgi.cgi

After having problems with CGI not being able to access /dev/i2c-1, restarting apache fixed the problem

$ sudo service apache2 restart

Raspberry Pi "pages" being serviced as CGI programs, reading room temperature with different I2C sensors:

merkle.hopto.org/cgi-bin/mcp9808.cgi
merkle.hopto.org/cgi-bin/tempcgi.cgi
merkle.hopto.org/cgi-bin/lm75a_cgi.cgi

Configure the screen size so VNC shows a larger display vs 640x480 when a display isn't attached to the Pi:

$ sudo leafpad /boot/config.txt

Find the following section and uncomment the framebuffer lines, or add your own.
I normally use a 1080P display...

# uncomment to force a console size. By default it will be display's size minus
# overscan.
#framebuffer_width=1280
#framebuffer_height=720
framebuffer_width=1920
framebuffer_height=1080