Script to setup SMB share for time machine backup

make-time-machine-work.sh

#!/bin/bash

###
### This is the script I use to setup time machine to work with my LinkSys attched NAS (USB 3.0 Hard Drive)
###

#### Configurable Parameters #########

SIZE=300g
NAME="Z.org Time Machine Backup"
#NAS=192.168.1.1
NAS=`netstat -rn |grep default |awk '{print $2}'`
SHARE=
DEFAULT_SHARE=timemachine
NAS_USER=timelord
NAS_PASSWORD=tardis

######################################

SIZE_PARAM="-size $SIZE"
MAC_ADDRESS=`ifconfig en0 | grep ether | sed s/://g | sed -e 's/ether//' | xargs`
HOST=`hostname -s`

if [ "$SIZE}" == "0" ]; then
    SIZE_PARAM=""
fi
DISK_IMAGE=${HOST}_${MAC_ADDRESS}
SPARSE_BUNDLE="${DISK_IMAGE}.sparsebundle"
GROUP_ID=`id -g`

if [ "$SHARE" == "" ]; then
    SHARE=$DEFAULT_SHARE
    echo "INFO: Finding shares on ${NAS}..."
    SHARES=`smbutil view //${NAS} |grep Disk |awk '{print $1}'`
    for s in $SHARES; do
        if (echo $s |grep -q time); then
            echo "INFO: Found potential share: '${s}'"
            SHARE=$s
        elif (echo $s |grep -q backup); then
            echo "INFO: Found potential share: '${s}'"
            SHARE=$s
        fi
    done
    echo "INFO: Using share: '${SHARE}'"
fi

SMB_URI="smb://${NAS_USER}@${NAS}/${SHARE}"
MOUNT=/Volumes/${SHARE}

echo "INFO: Writing sparse bundle: ./${HOST}_${MAC_ADDRESS} of size $SIZE"

defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1

if [ -d ./${SPARSE_BUNDLE} ]; then
    echo "WARN: ${SPARSE_BUNDLE} already found.  Not creating."
else

    sudo hdiutil create \
        $SIZE_PARAM \
        -type SPARSEBUNDLE \
        -nospotlight \
        -volname "${NAME}" \
        -fs "Case-sensitive Journaled HFS+" \
        -verbose ./${DISK_IMAGE}
fi

sudo chown -R $USERNAME:$GROUP_ID ${SPARSE_BUNDLE}

# This will create a 70GB sparse-bundle as a case-sensitive, journaled HFS+ 
# without spotlight indexing.  Substitute variables in red for values you
# need. Computername_MACaddress may be in the form of “DansComputer_001ec4b8f9b3


echo "INFO: Now connect to ${SMB_URI}"

echo "INFO: To view available shares, run: "
echo ""
echo "      smbutil view //${NAS}"
echo ""

echo ""
echo "WARN: Please type your password, and save it to your keychain."
echo ""
echo "      open ${SMB_URI}"

open ${SMB_URI}

while [ ! -r ${MOUNT} ]; do
    echo "INFO: Waiting for $SMB_URI to become available..."
    sleep 2
done

if [ -r ${MOUNT} ]; then
    echo "      cp -pvr ${SPARSE_BUNDLE} ${MOUNT}/"
    if [ -d ${MOUNT}/${SPARSE_BUNDLE} ]; then
        echo "WARN: Sparse Bundle already found.  Skipping copy."
    else
        cp -pvr ${SPARSE_BUNDLE} ${MOUNT}/
    fi
    
    open ${MOUNT}/${SPARSE_BUNDLE}

    TIME_MACHINE_MOUNT=`tmutil destinationinfo |grep 'Mount Point' |sed -e 's/.* : //'`
    TIME_MACHINE_VOLUME="/Volumes/${NAME}"

    if [ "${TIME_MACHINE_MOUNT}" != "${TIME_MACHINE_VOLUME}" ]; then
        echo "INFO: Setting time machine mount."
        echo "      sudo tmutil setdestination \"${TIME_MACHINE_VOLUME}\"/"
        sudo tmutil setdestination "${TIME_MACHINE_VOLUME}"/
    else
        echo "INFO: Time machine mount already set to ${TIME_MACHINE_VOLUME}."
    fi

else
    echo "ERROR: UNABLE TO READ $MOUNT"
    echo "       You must manually run:"
    echo "           cp -pvr ${SPARSE_BUNDLE} ${MOUNT}/"
fi

Copying from this https://support.apple.com/kb/PH14168?locale=en_US and https://appleclinic.wordpress.com/2008/10/30/time-machine-on-nas/

@aaronzirbes - nice gist 8-)