diff --git a/include/common.h b/include/common.h
index 18699c2..24a656a 100644
--- a/include/common.h
+++ b/include/common.h
@@ -1,6 +1,8 @@
 #ifndef _COMMON_H_
 #define _COMMON_H_
 
+extern char **init_command;
+extern char **crond_command;
 extern char **adguard_command;
 extern char **overture_command;
 extern char **domestic_dnsproxy_command;
diff --git a/src/cleardns.c b/src/cleardns.c
index 0582c44..a30ffd2 100644
--- a/src/cleardns.c
+++ b/src/cleardns.c
@@ -1,6 +1,13 @@
 #include <stdio.h>
+#include <string.h>
 #include "common.h"
 
+int debug_mode = 0;
+
+char *adguard_workdir = "/etc/cleardns/AdGuardHome";
+char *overture_config = "/etc/overture/config.yml";
+char *upstream_config = "/etc/cleardns/upstream.json";
+
 void show_command(char **command) {
     int num = 0;
     while(command[num] != NULL) {
@@ -9,11 +16,21 @@ void show_command(char **command) {
 }
 
 int main(int argc, char *argv[]) {
-    char *adguard_workdir = "/etc/cleardns/AdGuardHome";
-    char *overture_config = "/etc/overture/config.yml";
-    char *upstream_config = "/etc/cleardns/upstream.json";
+    for (char **p = argv; p < argv + argc; ++p) {
+        if (!strcmp(*p, "--debug")) { // --debug option
+            ++debug_mode;
+        }
+    }
+
+    load_start_command(adguard_workdir, overture_config, upstream_config, debug_mode);
 
-    load_start_command(adguard_workdir, overture_config, upstream_config, 0);
+    printf("[init]\n");
+    show_command(init_command);
+    printf("\n");
+
+    printf("[crond]\n");
+    show_command(crond_command);
+    printf("\n");
 
     printf("[AdGuardHome]\n");
     show_command(adguard_command);
diff --git a/src/common.c b/src/common.c
index 16792a3..a0325c2 100644
--- a/src/common.c
+++ b/src/common.c
@@ -3,6 +3,8 @@
 #include <string.h>
 #include "cJSON.h"
 
+char **init_command = NULL;
+char **crond_command = NULL;
 char **adguard_command = NULL;
 char **overture_command = NULL;
 char **domestic_dnsproxy_command = NULL;
@@ -111,7 +113,7 @@ char** dnsproxy_config(char *port, cJSON *json, int is_debug) { // generate dnsp
         }
     }
 
-    if (is_debug) { // verbose mode
+    if (is_debug) { // debug mode
         command_list = command_add_field(command_list, "--verbose");
     }
 
@@ -119,35 +121,53 @@ char** dnsproxy_config(char *port, cJSON *json, int is_debug) { // generate dnsp
 }
 
 void load_start_command(char *adguard_workdir, char *overture_config, char *upstream_config, int is_debug) {
-    // TODO: crond process
+    // init command
+    init_command = (char**)malloc(sizeof(char*) * 3);
+    init_command[0] = "sh";
+    init_command[1] = "/usr/bin/load";
+    init_command[2] = NULL;
+
+    // crond command
+    crond_command = (char**)malloc(sizeof(char*) * 2);
+    crond_command[0] = "crond";
+    crond_command[1] = NULL; // end sign
+    if (is_debug) { // debug mode
+        crond_command = command_add_field(crond_command, "-f"); // run in foreground
+        crond_command = command_add_field(crond_command, "-L");
+        crond_command = command_add_field(crond_command, "/dev/stdout");
+    }
 
     // AdGuardHome command
-    adguard_command = (char**)malloc(sizeof(char*) * 6);
+    adguard_command = (char**)malloc(sizeof(char*) * 7);
     adguard_command[0] = "AdGuardHome";
     adguard_command[1] = "-w";
     adguard_command[2] = adguard_workdir; // workdir for AdGuardHome
     adguard_command[3] = "-p";
     adguard_command[4] = "80"; // port for web manage
     adguard_command[5] = "--no-check-update"; // skip check update (invalid in docker)
-    if (is_debug) {
+    adguard_command[6] = NULL; // end sign
+    if (is_debug) { // debug mode
         adguard_command = command_add_field(adguard_command, "--verbose");
     }
 
     // overture command
-    overture_command = (char**)malloc(sizeof(char*) * 6);
+    overture_command = (char**)malloc(sizeof(char*) * 4);
     overture_command[0] = "overture";
     overture_command[1] = "-c";
     overture_command[2] = overture_config;
-    if (is_debug) {
+    overture_command[3] = NULL; // end sign
+    if (is_debug) { // debug mode
         overture_command = command_add_field(overture_command, "-v");
     }
 
     // dnsproxy command
-    cJSON *json = cJSON_Parse(read_file(upstream_config));
-    if (json == NULL) {
+    cJSON *json = NULL;
+    cJSON *json_root = cJSON_Parse(read_file(upstream_config));
+    if (json_root == NULL) {
         error_exit("JSON format error.");
+    } else {
+        json = json_root->child;
     }
-    json = json->child;
     while (json != NULL) {
         if (!strcmp(json->string, "domestic")) { // domestic dnsproxy config
             if (!cJSON_IsObject(json)) {
@@ -168,5 +188,5 @@ void load_start_command(char *adguard_workdir, char *overture_config, char *upst
     if (foreign_dnsproxy_command == NULL) {
         error_exit("Miss foreign DNS settings.");
     }
-    // TODO: free json object
+    cJSON_free(json_root);
 }