utmpx, wtmpx - utmpx and wtmpx database entry formats
The utmpx and wtmpx files are extended database files that have
superseded the obsolete utmp and wtmp database files.
The utmpx database contains user access and accounting
information for commands such as who(1), write(1), and
login(1). The wtmpx database contains the history of user
access and accounting information for the utmpx database.
Applications should not access these databases directly, but should use the
functions described on the getutxent(3C) manual page to interact with
the utmpx and wtmpx databases to ensure that they are maintained
user access and administration information
history of user access and administrative