PiDP-8/I Software

    simulator correct?  Does OS/8 run?  Are there any complaints from
    SIMH, such as about insufficient CPU power?

4.  Do the final inside-the-image steps:

        $ ./bosi prepare

5.  Move the SD card to a USB reader plugged into the Pi, boot the Pi
    from its prior SD card, and shrink the OS image:

        $ wget https://tangentsoft.com/bosi
        $ chmod +x bosi
        $ ./bosi shrink

6.  Move the USB reader to the Mac,¹ then say:

        $ bosi image [nls]

    For the ILS images, you can give "ils" as a parameter or leave it
    blank.

7.  The prior step rewrote the SD card with the image file it created.
    Boot it up and make sure it still works.  If you're happy with it,
    give this command *on the desktop PC*.

        $ bosi finish [nls]

    As above, the parameter can be "ils" or left off for the ILS images.

[os]: https://www.raspberrypi.org/software/operating-systems/

# Display the usage message
function usage() {
    cat <<USAGE
usage: $0 <verb> [tag]

    The available verbs are init, build, prepare, shrink, image, and finish.

    You may include a tag parameter with the 'image' and 'finish' verbs
    to override the default tag ('ils') used in image and zip file
    outputs.

    See RELEASE-PROCESS.md for more info.

    /usr/sbin/shutdown -h +1

    # Must be last, else later "sudo" will fail on the expired password
    echo 'pidp8i:edsonDeCastro1968' | sudo chpasswd &&
        sudo passwd -e pidp8i
}


# Shrink the filesystem on the OS SD card we're about to image to just a
# bit bigger than required to hold its present contents.
#
# The extra 100 megs in the arithmetic below accounts for the /boot
# partition, since the `resizepart` command takes a partition end value,
# not a size value.
#
# We don't calculate the actual end of the /boot partition and use that
# value because we want a bit of slack space to buy time for an end user
# who neglects to expand the card image into the free space available on
# their SD card after first boot.
function do_shrink() {
    test "$USER" = "root" || exec sudo $this shrink

    set -x

    umount /dev/sda2 || true    # might auto-mount, might not
    e2fsck -f /dev/sda2         # resize2fs demands it

    # Pack it down tight
    blocks=$(
        resize2fs -M /dev/sda2 2>&1 |
        grep 'blocks long' | 
        grep -wo '[0-9]\+'
    )
    if [ "$blocks" -gt 0 ]
    then
        # And now give it a bit of breathing room
        parted /dev/sda resizepart 2 $(($blocks * 4096 + 10**8))b
        resize2fs /dev/sda2
        poweroff
    else
        echo "Failed to extract new filesystem size from resize2fs!"
        echo
        exit 1
    fi
}


# This script images the OS SD card in a USB reader on a macOS box.
function do_image() {
    dev=UNKNOWN
    ps=UNKNOWN
    hb=no
    rp=UNKNOWN

# Main routine
set -e
case "$verb" in
    in*) do_init ;;
    bu*) do_build ;;
    pr*) do_prepare ;;
    sh*) do_shrink ;;
    im*) do_image ;;
    fi*) do_finish ;;
    *)   usage ;;
esac