The files etcpasswd and etcshadow can be manually edited Why

The files /etc/passwd and /etc/shadow can be manually edited. Why would you not want to do this? What is the appropriate way to modify these files?

Solution

Suppose root opened /etc/passwd file to edit it. Meanwhile if user wants to change his password then will not be entered into the file.
To avoid this problem file is locked first and then only root can edit the file. If user wants to change password he will get \"passwd: Authentication token lock busy\" message

Appropriate way to modify these files is

1. First login as root user
Run \"sudo su\" and enter root password when prompted

2. Then run \"vipw -s\" to edit /etc/passwd file