Passwdbyname

Passwdbyname is a term used in some Unix-like environments to describe a function or utility that retrieves a user account entry from the system password database by user name. In practice, it accepts a string that identifies a user (for example, a login name) and returns a structured record containing account fields such as the user name, user ID, group ID, real name (GECOS), home directory, and login shell.

On traditional Unix implementations, the record is typically read from the local passwd file (and, where present, supplemented by the shadow file for password data). Many modern systems store the password hash in /etc/shadow, with the passwd entry containing a placeholder instead of the hash. Some programming environments implement passwdbyname as a wrapper around standard POSIX interfaces such as getpwnam or getpwnam_r; others may expose similar functionality through higher-level libraries or directory services (LDAP, NIS, etc.).

Because the information relates to user credentials, access may be restricted and publicly exposing password hashes is avoided; tools typically return only non-sensitive fields unless running with elevated privileges. Use cases include user authentication, account validation, system auditing, and applications that adapt behavior based on the target user's attributes.

See also: getpwnam, /etc/passwd, /etc/shadow, pwd module.