Removed or deleted /etc/passwd file accidentally what to do now?

Loss of some important files such as /etc/passwd through your stupidity is tough. The Debian system makes regular backups of them in /var/backups/. When you restore these files, you may manually have to set the proper permissions.

     # cp /var/backups/passwd /etc/passwd
     # chmod 644 /etc/passwd
this /var/backups folder consists of the following files
 dpkg.status.0  gshadow.bak     infodir.bak  shadow.bak group.bak      inetd.conf.bak  passwd.bak

 Find or identify which version of  debian  you are running?

 This can be checked in /etc/debian_version file