Auto start file

Hello, i am making .sh file an i this file i write
cd /usrda
mkdir hello
and i follow auto start guide it work fine when my modem(quectel EC21) reboot but when i execute my c file under same directory it not workmy .sh script is
cd /usrda
kindly correct me

You can refer to the following documents to configure
Quectel_EC2x_Series_QuecOpen_Auto-startup_Service_Guide_V1.0.pdf (429.1 KB)