[ "$SHARED_DIRECTORY" ] || \
{ FAIL_ON_ERROR=true skip_env "$0 Empty SHARED_DIRECTORY" && exit 0; }
+check_shared_dir $SHARED_DIRECTORY ||
+ error "$SHARED_DIRECTORY isn't a shared directory"
+
[ -n "$CLIENTS" ] || \
{ FAIL_ON_ERROR=true skip_env "$0 Need two or more remote clients" && exit 0; }