How can I lock/unlock passwd file?
 

Hello Friends
How can I lock/unlock password file

I'll assume you mean /etc/passwd.

I am not aware of a mechanism to lock or unlock system files. In things like word processors, there are tools to have their files be password protected.

The method to control access to system files is the permission bits. These are set using chmod. You can also edit certain files to do other specific things. For example, removing the first "x" in an entry in /etc/passwd will allow login with no password.

Please give more information about what exactly you are trying to do.

I moved your post to its own thread. Please ask new questions in new threads in the future.