v7 man page for who

WHO(1)							      General Commands Manual							    WHO(1)

NAME
       who  -  who is on the system

SYNOPSIS
       who [ who-file ] [ am I ]

DESCRIPTION
       Who, without an argument, lists the login name, terminal name, and login time for each current UNIX user.

       Without	an argument, who examines the /etc/utmp file to obtain its information.  If a file is given, that file is examined.  Typically the
       given file will be /usr/adm/wtmp, which contains a record of all the logins since it was created.  Then	who  lists  logins,  logouts,  and
       crashes	since  the  creation of the wtmp file.	Each login is listed with user name, terminal name (with `/dev/' suppressed), and date and
       time.  When an argument is given, logouts produce a similar line without a user name.  Reboots produce a line with `x' in the place of  the
       device name, and a fossil time indicative of when the system went down.

       With two arguments, as in `who am I' (and also `who are you'), who tells who you are logged in as.

FILES
       /etc/utmp

SEE ALSO
       getuid(2), utmp(5)

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