fix: use mail command

scripts/entrypoint.sh

@@ -9,7 +9,7 @@ if [[ "$1" == "rclone" ]]; then
     exit 0
 fi
 
-# mailx test
+# mail test
 if [[ "$1" == "mail" ]]; then
     export_env_file
     init_env_mail

scripts/includes.sh

@@ -82,7 +82,7 @@ function check_dir_exist() {
 }
 
 ########################################
-# Send mail by mailx.
+# Send mail by s-nail.
 # Arguments:
 #     mail subject
 #     mail content
@@ -94,7 +94,7 @@ function send_mail() {
         local MAIL_VERBOSE="-v"
     fi
 
-    echo "$2" | mailx ${MAIL_VERBOSE} -s "$1" ${MAIL_SMTP_VARIABLES} "${MAIL_TO}"
+    echo "$2" | mail ${MAIL_VERBOSE} -s "$1" ${MAIL_SMTP_VARIABLES} "${MAIL_TO}"
     if [[ $? != 0 ]]; then
         color red "mail sending failed"
     else