How to add an user in OpenWrt using command or python?

According to this link https://vladimir-ivanov.net/create-user-without-useradd-command-openwrt/ I did all the steps, but I did not add any user in OpenWrt /etc/passwd file contains the encrypted password, that should be in /etc/shadow. I edited and added user to the /etc/passwd and then I used the "passwd testuser" command. It asked me to set twice my password and added the encrypted password to the /etc/passwd. But it did not add user or write anything to the /etc/shadow. I did the same in Ubuntu and it worked. But I need to do it in OpenWrt.

Solution

You should install the shadow-useradd package:

opkg update
opkg install shadow-useradd