bin/srsync-incremental: remove target directory if empty

[config/dotfiles.git] / bin / srsync-incremental

diff --git a/bin/srsync-incremental b/bin/srsync-incremental
index a76bf728ec76992f06b2576500ae61494ccda9d3..187e6b6d84a165109c218c2f2b3526f14665947f 100755 (executable)
--- a/bin/srsync-incremental
+++ b/bin/srsync-incremental
@@ -5,7 +5,7 @@
 # Thanks to http://www.sanitarium.net/golug/rsync_backups_2010.html for the
 # idea.
 
-# Copyright (C) 2011-2012  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
@@ -21,32 +21,46 @@
 # 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
-shift
 
-dest=`echo backup-*`
-if [ "x$dest" != 'xbackup-*' ]; then
-    dest="`pwd`/`ls -1d backup-* | tail -n1`"
-fi
+cd "$1"
+shift
 
-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 [ -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 "$target_tmp"
 rsync \
-    --verbose --human-readable \
-    --archive --hard-links --numeric-ids --one-file-system \
+    --verbose --itemize-changes --human-readable \
+    --archive --acls --xattrs --hard-links --sparse --numeric-ids \
+    --one-file-system \
     --link-dest="$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"