Is passwd file always in /etc/passwd?

Question

So, I'm writing a script that needs to modify the such a file but from the partition of a non booted OS (for example from a livCD to a OS installed on another drive) and I was wondering if, given I mount the Drive correctly, I will always find it in /path/to/mounted/drive/etc/passwd or if it is possible/common to have it somewhere else. Moreover, if it is possible, do I have a quicker way to find it than to use the find bash command?

Answer 1

In file /etc/libuser.conf there are two sections:

[files]
Configures the files module, which manages /etc/group and /etc/passwd. The configuration variables are probably useful only for libuser development.
    directory - The directory containing the group and passwd files.  Default value is /etc.
    nonroot - Allow module initialization when not invoked as the root user if the value is yes.

[shadow]
Configures the files module, which manages /etc/gshadow and /etc/shadow. The configuration variables are probably useful only for libuser development.
    directory - The directory containing the gshadow and shadow files.  Default value is /etc.
    nonroot - Allow module initialization when not invoked as the root user if the value is yes.

So to answer your question: yes, the location of passwd file can be changed.

You should also be aware that modifying passwords from outside the system can be tricky if SELinux is enabled.