removable-backup

#!/bin/bash
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#
# Backup the system to the removable drive in /dev/sdd1 with duplicity.
#
set -e -o pipefail

# Our mount expectations.  There are two physical disks and either (or both)
# could be connected.  We use the first one we find.
dir1=/removable/backup1
device1=/dev/disk/by-id/usb-WD_My_Passport_25E1_57584631413437364330354C-0:0-part1
dir2=/removable/backup2
device2=/dev/disk/by-id/usb-WD_My_Passport_25E2_57584A3141373741324B4A48-0:0-part1

#-----------------------------------------------------------------------------
# Which device and dir should we use?

# Look for them in order.
dir=
device=
for i in 1 2; do
  ldir=dir$i
  ldevice=device$i
  echo -n "Looking for ${!ldir} device ${!ldevice} . . ."
  if [ -e "${!ldevice}" ]; then
    dir=${!ldir}
    device=${!ldevice}
    echo " found!"
    break
  fi
  echo " not found."
done
if [ -z "$dir" -o -z "$device" ]; then
  echo "Couldn't find any devices connected."
fi
unset ldir ldevice

#-----------------------------------------------------------------------------
# Pre-flight check.

# Figure out where $1 is mounted and echo it.
function find-dir-mount ()
{
  perl -ne 'if(m!^(\S+)\s+('$1')\s!){ print "$1\n"; last}' /proc/mounts
}

# See if the device is mounted and where.
dev=$(find-dir-mount $dir)
if [ -z "$dev" ]; then
  echo -n "Did not find $dir mounted.  Attempt to mount it now [y/N]? "
  read input
  if [ "$input" != "y" ]; then
    echo "Not confirmed."
    exit 1
  fi
  mount $dir

  # Auto unmount on exit if we can
  trap 'echo "Unmounting $dir since we mounted it."; umount $dir' EXIT TERM INT QUIT
  echo "Will unmount $dir when the backup terminates."
fi

# Check again.
dev=$(find-dir-mount $dir)
if [ -z "$dev" ]; then
  echo  "Did not found $dir mounted."
  exit 1
fi

# Confirm that $dev starts with '/dev/'
if [ "$(echo "$dev" |cut -b1-5)" != "/dev/" ]; then
  echo "Can't determine mount point of $dir; found: $dev"
  exit 1
fi
echo "Found $dir mounted on $dev"

# Check identity of $dev
if [ "$(readlink -e $device)" != "$dev" ]; then
  echo "Could not confirm that $dev is $device."
  exit 1
fi
echo "Confirmed that $dev is the expected device $device"

#-----------------------------------------------------------------------------
# Prep.

# Show the collection status.
echo "Gathering current collection status . . ."
duplicity collection-status file://$dir/duplicity

# First display all but the most recent full backup to prepare for deleting
# them.
duplicity remove-all-but-n-full 1 file://$dir/duplicity
echo -n "Delete all but the most recent full backup [y/N]? "
read input
if [ "$input" = "y" ]; then
  duplicity remove-all-but-n-full 1 file://$dir/duplicity --force
else
  echo "Leaving all exiting backups in place."
fi

#-----------------------------------------------------------------------------
# Print an approximate usage total.

du -hsc \
  --exclude /home/spencer/.cache \
  --exclude /root/.cache \
  --exclude /var/autofs \
  --exclude /var/cache \
  --exclude /var/lib/mythtv \
  --exclude /var/lock \
  --exclude /var/run \
  /boot \
  /data \
  /etc \
  /home \
  /opt \
  /root \
  /sbin \
  /usr/local \
  /var

#-----------------------------------------------------------------------------
# Perform the backup.  This will prompt for the passphrase.

duplicity \
    --progress full \
    --exclude-device-files \
    \
    --include /boot \
    --include /data \
    --include /etc \
    \
    --exclude '/home/*/.cache' \
    --include /home \
    \
    --include /opt \
    --exclude /root/.cache \
    --include /root \
    --include /sbin \
    --include /usr/local \
    \
    --exclude /var/autofs \
    --exclude /var/cache \
    --exclude /var/lib/mythtv \
    --exclude /var/lock \
    --exclude /var/run \
    --exclude /var/tmp \
    --include /var \
    \
    --exclude '**' \
    \
    / file://$dir/duplicity

#-----------------------------------------------------------------------------
# Finished

# How to power it off:
echo "To power off the drive:"
echo "udisksctl power-off -b $dev"

echo "Done."


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