How can a non-privileged user on a Unix system determine if shadow passwords are being used?

The filename /etc/password does not exist as a standard Unix file; the correct filename is /etc/passwd, making this option based on an incorrect file reference.

When shadow passwords are enabled, /etc/shadow holds the actual password hashes, and the second colon-delimited field uses markers such as 'x' or '!!' to denote shadow-enabled or locked accounts. Examining this field directly confirms whether the shadow password mechanism is configured and active on the system.

Shadow passwords do not replace /etc/passwd; both files coexist, with /etc/passwd retaining user account metadata while /etc/shadow stores the password hashes.

/etc/shadow uses colon-delimited fields, not comma-delimited fields, so referencing comma-delimited NULL values reflects a fundamentally incorrect understanding of the file format.