[Solved] You don't exist, go away!

Today My system gives me a funny message when a using ssh command:

"You don't exist, go away!"

  after that i restarted my system and trying to logging my system  its unable to read users file (/etc/passwd).


then i reboot my system and i logged in single user mode and trying to read /etc/passwd file but its error that file was not in txt mode and after that i have checked another file /etc/shadow that file also not txt readable after that i have checked /etc/passwd- and /etc/shadow- file and replce the /etc/shadow and /etc/passwd file 


Now i have logged on my system and working file

cp /etc/passwd- /etc/passwd
cp /etc/shadow- /etc/shadow