Fix linting issue

acme.sh

@@ -1999,7 +1999,7 @@ _post() {
     if [ "$_ret" != "0" ]; then
       _err "Please refer to https://www.gnu.org/software/wget/manual/html_node/Exit-Status.html for error code: $_ret"
     fi
-    if echo $_WGET | grep -q " -d " 2> /dev/null; then
+    if echo $_WGET | grep -q " -d " 2>/dev/null; then
       # Demultiplex wget debug output
       cat "$HTTP_HEADER" >&2
       _sed_i '/^[^ ][^ ]/d; /^ *$/d' "$HTTP_HEADER"
@@ -2059,14 +2059,14 @@ _get() {
     _debug "_WGET" "$_WGET"
     if [ "$onlyheader" ]; then
       _wget_out = "$($_WGET --user-agent="$USER_AGENT" --header "$_H5" --header "$_H4" --header "$_H3" --header "$_H2" --header "$_H1" -S -O /dev/null "$url" 2>&1)"
-      if echo $_WGET | grep -q " -d " 2> /dev/null; then
+      if echo $_WGET | grep -q " -d " 2>/dev/null; then
         # Demultiplex wget debug output
         echo "$_wget_out" >&2
         echo "$_wget_out" | sed '/^[^ ][^ ]/d; /^ *$/d; s/^  //g' -
       fi
     else
       $_WGET --user-agent="$USER_AGENT" --header "$_H5" --header "$_H4" --header "$_H3" --header "$_H2" --header "$_H1" -S -O - "$url" 2>"$HTTP_HEADER"
-      if echo $_WGET | grep -q " -d " 2> /dev/null; then
+      if echo $_WGET | grep -q " -d " 2>/dev/null; then
         # Demultiplex wget debug output
         cat "$HTTP_HEADER" >&2
         _sed_i '/^[^ ][^ ]/d; /^ *$/d' "$HTTP_HEADER"