diff --git a/dnsapi/dns_arvancdn.sh b/dnsapi/dns_arvancdn.sh
index db1dfd13..cecc1e0d 100644
--- a/dnsapi/dns_arvancdn.sh
+++ b/dnsapi/dns_arvancdn.sh
@@ -1,4 +1,4 @@
-#!/usr/bin/env #!/bin/sh
+#!/usr/bin/env bash
 
 # Author: Mohammad Ali Sarbanha <sarbanha at yahoo dot com>
 # Repository: https://github.com/sarbanha/acme.sh-dnsapi-dns_arvancdn
@@ -16,30 +16,30 @@ dns_arvancdn_add() {
   _debug "dns_arvan_add(): Started"
 
   ARVAN_API_KEY="${ARVAN_API_KEY:-$(_readaccountconf_mutable ARVAN_API_KEY)}"
-  if [ -z $ARVAN_API_KEY ]; then
+  if [ -z "${ARVAN_API_KEY}" ]; then
     ARVAN_API_KEY=""
     _err "dns_arvan_add(): ARVAN_API_KEY has not been defined yet."
     _err "dns_arvan_add(): export ARVAN_API_KEY=\"---YOUR-API-KEY---\""
     return 1
   fi
-  _saveaccountconf_mutable ARVAN_API_KEY "$ARVAN_API_KEY"
+  _saveaccountconf_mutable ARVAN_API_KEY "${ARVAN_API_KEY}"
 
-  _debug "dns_arvan_add(): Check domain root zone availability for $_fulldomain"
-  _zone=$(_get_root $_fulldomain)
+  _debug "dns_arvan_add(): Check domain root zone availability for ${_fulldomain}"
+  _zone=$(_get_root "${_fulldomain}")
   if [ $? -ne 0 ]; then
-    _err "dns_arvan_add(): Root zone for $_fulldomain not found!"
+    _err "dns_arvan_add(): Root zone for ${_fulldomain} not found!"
     return 1
   fi
 
-  _record_name=$(echo $_zone | sed "s/\.\..*//")
-  _zone=$(echo $_zone | sed "s/.*\.\.//")
+  _record_name=$(echo "${_zone}" | sed "s/\.\..*//")
+  _zone=$(echo "${_zone}" | sed "s/.*\.\.//")
 
-  _debug "dns_arvan_add(): fulldomain $_fulldomain"
-  _debug "dns_arvan_add(): textvalue $_challenge"
-  _debug "dns_arvan_add(): domain $_record_name"
-  _debug "dns_arvan_add(): domain $_zone"
+  _debug "dns_arvan_add(): fulldomain ${_fulldomain}"
+  _debug "dns_arvan_add(): textvalue ${_challenge}"
+  _debug "dns_arvan_add(): domain ${_record_name}"
+  _debug "dns_arvan_add(): domain ${_zone}"
 
-  _record_add $_record_name $_zone $_challenge
+  _record_add "${_record_name}" "${_zone}" "${_challenge}"
 
 }
 
@@ -50,26 +50,26 @@ dns_arvancdn_rm(){
   _challenge=$2
 
   ARVAN_API_KEY="${ARVAN_API_KEY:-$(_readaccountconf_mutable ARVAN_API_KEY)}"
-  if [ -z $ARVAN_API_KEY ]; then
+  if [ -z "${ARVAN_API_KEY}" ]; then
     ARVAN_API_KEY=""
     _err "dns_arvan_rm(): ARVAN_API_KEY has not been defined yet."
     _err "dns_arvan_rm(): export ARVAN_API_KEY=\"---YOUR-API-KEY---\""
     return 1
   fi
 
-  _zone=$(_get_root $_fulldomain)
+  _zone=$(_get_root "${_fulldomain}")
   if [ $? -ne 0 ]; then
-    _err "dns_arvan_rm(): Root zone for $_fulldomain not found!"
+    _err "dns_arvan_rm(): Root zone for ${_fulldomain} not found!"
     return 1
   fi
 
-  _record_name=$(echo $_zone | sed "s/\.\..*//")
-  _zone=$(echo $_zone | sed "s/.*\.\.//")
+  _record_name=$(echo "${_zone}" | sed "s/\.\..*//")
+  _zone=$(echo "${_zone}" | sed "s/.*\.\.//")
 
 
-  _record_id=$(_record_get_id $_zone $_challenge)
+  _record_id=$(_record_get_id "${_zone}" "${_challenge}")
 
-  _record_remove $_zone $_record_id
+  _record_remove "${_zone}" "${_record_id}"
 
 }
 
@@ -83,30 +83,30 @@ _get_root(){
   _zone=$_fulldomain
 
   export _H1="Content-Type: application-json"
-  export _H2="Authorization: apikey $ARVAN_API_KEY"
+  export _H2="Authorization: apikey ${ARVAN_API_KEY}"
 
-  _response=$(_get $ARVAN_CDN_API/domains)
-  _domains_list=( $( echo $_response | grep -Poe '"domain":"[^"]*"' | sed 's/"domain":"//' | sed 's/"//') )
+  _response=$(_get "${ARVAN_CDN_API}/domains")
+  _domains_list=( $( echo "${_response}" | grep -Poe '"domain":"[^"]*"' | sed 's/"domain":"//' | sed 's/"//') )
 
-  _debug2 "_get_root(): $_response"
-  _debug2 "_get_root(): $_domains_list"
+  _debug2 "_get_root(): reponse ${_response}"
+  _debug2 "_get_root(): domains list ${_domains_list}"
 
   #Fibding a matching Zone
-  while [[ ! -z $_zone ]]; do
-    for tmp in ${_domains_list[@]}; do
-      if [ $tmp = $_zone ]; then
+  while [[ ! -z "${_zone}" ]]; do
+    for tmp in "${_domains_list[@]}"; do
+      if [ "${tmp}" = "${_zone}" ]; then
         break 2
       fi
     done
-    _zone=$(echo $_zone | sed 's/^[^.]*\.\?//')
+    _zone=$(echo "${_zone}" | sed 's/^[^.]*\.\?//')
   done
-  if [ -z $_zone ]; then
+  if [ -z "${_zone}" ]; then
     _debug2 "_get_root(): Zone not found on provider"
     exit 1
   fi
 
-  _marked_zone=$(echo $_fulldomain | sed "s/^\(.*\)\.\(${_zone}\)$/\1..\2/")
-  echo $_marked_zone
+  _marked_zone=$(echo "${_fulldomain}" | sed "s/^\(.*\)\.\(${_zone}\)$/\1..\2/")
+  echo "${_marked_zone}"
 
 }
 
@@ -118,13 +118,13 @@ _record_add(){
   _challenge=$3
 
   export _H1="Content-Type: application-json"
-  export _H2="Authorization: apikey $ARVAN_API_KEY"
+  export _H2="Authorization: apikey ${ARVAN_API_KEY}"
 
-  _payload="{\"type\":\"txt\",\"name\":\"$_record_name\",\"cloud\":false,\"value\":{\"text\":\"$_challenge\"},\"ttl\":120}"
-  _response=$(_post "$_payload" "$ARVAN_CDN_API/domains/$_zone/dns-records" "" "POST" "application/json" | _base64)
+  _payload="{\"type\":\"txt\",\"name\":\"${_record_name}\",\"cloud\":false,\"value\":{\"text\":\"${_challenge}\"},\"ttl\":120}"
+  _response=$(_post "${_payload}" "${ARVAN_CDN_API}/domains/${_zone}/dns-records" "" "POST" "application/json" | _base64)
 
-  _debug2 "_record_add(): " $_response
-  _debug2 "      Payload: " $_payload
+  _debug2 "_record_add(): ${_response}"
+  _debug2 "      Payload: ${_payload}"
 }
 
 #Usage: _record_get_id zone challenge
@@ -134,13 +134,13 @@ _record_get_id(){
   _challenge=$2
 
   export _H1="Content-Type: application-json"
-  export _H2="Authorization: apikey $ARVAN_API_KEY"
+  export _H2="Authorization: apikey ${ARVAN_API_KEY}"
 
-  _response=$(_get $ARVAN_CDN_API/domains/$_zone/dns-records/?type=txt\&search=$_challenge | _json_decode | _normalizeJson | grep -Eo '"id":.*?,"value":\{"text":".*?"\}' | sed 's/"id":"\([^"]*\)".*/\1/')
-  _debug2 "_record_get_id(): " $_response
+  _response=$(_get "${ARVAN_CDN_API}/domains/${_zone}/dns-records/?type=txt\&search=${_challenge}" | _json_decode | _normalizeJson | grep -Eo '"id":.*?,"value":\{"text":".*?"\}' | sed 's/"id":"\([^"]*\)".*/\1/')
+  _debug2 "_record_get_id(): ${_response}"
 
 
-  echo "$_response"
+  echo "${_response}"
 
 }
 
@@ -153,9 +153,9 @@ _record_remove(){
   export _H1="Content-Type: application-json"
   export _H2="Authorization: apikey $ARVAN_API_KEY"
 
-  _response=$(_post "" $ARVAN_CDN_API/domains/$_zone/dns-records/$_record_id "" "DELETE" "application/json")
+  _response=$(_post "" "$ARVAN_CDN_API/domains/$_zone/dns-records/$_record_id" "" "DELETE" "application/json")
 
   _debug  "_record_remove(): ACME Challenge Removed"
-  _debug2 "        Response: " $_response
+  _debug2 "        Response: $_response"
 
 }