# Thanks to http://www.sanitarium.net/golug/rsync_backups_2010.html for the
# idea.
-# Copyright (C) 2011-2012 Simon Ruderich
+# Copyright (C) 2011-2014 Simon Ruderich
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# along with this program. If not, see <http://www.gnu.org/licenses/>.
-if [ $# -lt 2 ]; then
+set -eu
+
+if test "$#" -lt 2; then
echo "Usage: $0 <backups-directory> <arguments to rsync>" >&2
echo
echo "Note: The target directory is the _first_ argument!" >&2
exit 2
fi
-cd "$1" || exit 1
+
+cd "$1"
shift
-dest=`echo backup-*`
-if [ "x$dest" != 'xbackup-*' ]; then
- # -F and grep is used to list only directories, zsh's *(/) would be great.
- dest="`pwd`/`ls -1dF backup-* | grep / | tail -n1`"
-fi
+# Get absolute path to last backup directory.
+for x in backup-*; do
+ test -d "$x" || continue
+ dest="../$x" # relative to destination directory
+done
target=backup-`date '+%Y-%m-%d-%H-%M-%S'`
-if [ -d current ]; then
+if test -d current; then
echo "Target directory 'current' already exists, aborting." >&2
exit 1
fi
mkdir current
rsync \
--verbose --itemize-changes --human-readable \
- --archive --hard-links --numeric-ids --one-file-system \
+ --archive --hard-links --sparse --numeric-ids --one-file-system \
--link-dest="$dest" \
"$@" current \
-&& mv current "$target"
+|| {
+ # Try to remove "current" without changing the exit code. In case the
+ # connection failed without transferring any files, we want the next
+ # backup to be able to run.
+ code=$?
+ rmdir current 2>/dev/null || true
+ exit $code
+}
+mv current "$target"