rotate backup only if current backup ok

script.sh

@@ -2,17 +2,36 @@
 
 set -eu
 
+if [ "$#" -ne 1 ] ; then
+  echo "Usage: $O dir_to_backup"
+  exit 1
+fi
+
+test -d "$1" || { 
+  echo "$1 don't exist or not a dir" 
+  exit 2
+}
+
+if [ ! -d "$1" ] ; then
+  echo "$1 don't exist or not a dir"
+  exit 2
+fi
+
 src=$1
 dest=/var/backups/$(date -I)
 
-mkdir -p ${dest}
+mkdir -p "${dest}" || exit 3
 
 # tar cpzf /var/backups/$(date -I)/etc.tgz /etc
-tar cpzf ${dest}/${src}.tgz ${src}
+tar cpzf "${dest}/${src}.tgz" "${src}"
+ret=$?
 
-find ${dest} -maxdepth 1 -type f -mtime +7 -exec echo rm {} \;
+if [ $ret -eq 0 ] ; then
+  find "${dest}"  -maxdepth 1 -type f -mtime +7 -exec echo rm {} \;
+fi
 
 
 
 
-exit 0
+
+exit $ret