I am trying too do following command under entware-alternative:
#adduser hu #addgroup jk #usermod -aG jk hu # add "hu" to group "jk" #mkdir tf #chmod 770 tf #chgrp jk tf #su hu $cd tf $touch aaa
And it success.
My OS is Android, it doesn't have /etc/passwd and /etc/groups.
And it doesn't have pam_unix.so either.
Even though entware created /opt/etc/passwd and /opt/etc/groups. How linux know group "jk" has user "hu"?
How does linux know these information are stored in /opt/etc/passwd and /opt/etc/groups?
Bash and openssh-server can recognize my username correctly, I guess it were recompiled to read /opt/etc/passwd instead of /etc/passwd.
But file operation are managed by kernel I guess, how does kernel know this uid is under that gid?