# Thanks to http://www.sanitarium.net/golug/rsync_backups_2010.html for the
# idea.
-# Copyright (C) 2011-2013 Simon Ruderich
+# Copyright (C) 2011-2017 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/>.
-set -e
+set -eu
if test "$#" -lt 2; then
echo "Usage: $0 <backups-directory> <arguments to rsync>" >&2
fi
-cd "$1" || exit 1
+cd "$1"
shift
-dest=`echo backup-*`
-if test "x$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
-
-target=backup-`date '+%Y-%m-%d-%H-%M-%S'`
+# Get path to last backup directory.
+dest=./
+for x in backup-*; do
+ test -d "$x" || continue
+ dest="../$x" # relative to destination directory
+done
-if test -d current; then
- echo "Target directory 'current' already exists, aborting." >&2
- exit 1
-fi
+target="backup-$(date '+%Y-%m-%d-%H-%M-%S')"
+target_tmp="partial-$target"
-mkdir current
+mkdir "$target_tmp"
rsync \
--verbose --itemize-changes --human-readable \
- --archive --hard-links --numeric-ids --one-file-system \
+ --archive --acls --xattrs --hard-links --sparse --numeric-ids \
+ --one-file-system \
--link-dest="$dest" \
- "$@" current \
-&& mv current "$target"
+ "$@" "$target_tmp" \
+|| {
+ # Try to remove the target directory without changing the exit code. In
+ # case the connection failed without transferring any files, we want to
+ # remove the empty directory.
+ code=$?
+ rmdir "$target_tmp" 2>/dev/null || true
+ exit $code
+}
+# --dry-run (-n) creates an empty directory. Remove it to prevent using it for
+# further incremental backups (which would do a full backup).
+rmdir "$target_tmp" 2>/dev/null && exit 0 || true
+
+mv "$target_tmp" "$target"