Lightroom 6 re-compressing backup script

backup-lrcat

#!/bin/bash
# This script re-compresses an Lr6 zipped lrcat file using xz, which is
# much more efficient.  Oddly, it's actually more compatible, since Lr6.0
# uses a variant of Zip that won't even open using built-in OS X utilities.

# Open Lightroom and wait for it to exit. You must then say Cmd-Opt-,
# and tell Lr to "back up catalog when Lightroom next exits", then
# exit. If Lr is already running, this will just wait, so it is not
# important whether you run this script before or after Lr is running.
#
# Don't rewrite this as "if ! time..." because that causes it to use
# /usr/bin/time instead of the builtin, which has harder to read output.
time open -Wa 'Adobe Lightroom'
if [ "$?" != 0 ]
then
	echo Lightroom killed!
	echo
	exit 1
fi

# Make sure the backup volume is mounted.
cbdir=/Volumes/backups/catalogs
if [ ! -d $cbdir ]
then
	echo Catalog backup directory $cbdir missing!
	echo Did you forget to mount it?
	echo
	exit 1
fi

# Build zip file names.  The "20" prefix on the zip file is meant to avoid
# searching through obviously-wrong subdirectories for *.lrcat.zip.  This
# will break in about 85 years, by which time I won't care. :)
zipcat="$(ls ~/tmp/20*/*.lrcat.zip | head -1)"
compcat=$cbdir/$(date +%Y-%m-%d).lrcat.xz

# Did we find the zipped catalog file?
if [ ! -f "$zipcat" ]
then
	echo "Could not find zipped LR catalog backup file:"
	echo "    $zipcat"
	echo
	exit 1
fi

# Make sure we're not running after a previous crash of this script.
tempcat="$(echo $zipcat | sed -e 's/\.zip$//')"
if [ -e "$tempcat" ]
then
	echo "The zipped LR catalog has already been unpacked and not cleaned"
	echo "up.  Cowardly refusing to stomp on it."
	echo
	exit 1
fi

# The meat: Unpack the *.lrcat.zip file with The Unarchiver, then
# recompress it with xz(1).
echo 'Backup complete; recompressing it...' &&
	open -Wa 'The Unarchiver' "$zipcat" &&
	time xz -c < "$tempcat" > "$compcat" &&
	echo -n 'Done!  ' &&
	rm -f "$tempcat" "$zipcat" &&
	find ~/tmp -empty -delete &&
	echo 'Zipped catalog backup removed.'