Use basic regexp in grep

scripts/backup.sh

@@ -102,7 +102,9 @@ do
         fi
 
         # Retrieve file state (Added, Modified, Deleted)
-        STATE=$(${GIT} ${GIT_OPTS[@]} show --name-status --pretty= ${COMMIT_SHA} | grep -E "^..${FILE}\$" | cut -f1)
+        # Using basic regex as we want to avoid checking '()' or other complex regex patterns.
+        # This is suboptimal and error prone. But it passes the full backup :-)
+        STATE=$(${GIT} ${GIT_OPTS[@]} show --name-status --pretty= ${COMMIT_SHA} | grep -G "^..${FILE}\$" | cut -f1)
 
         if test "${STATE}" != "D"
         then