who  -  who is on the system

     who [ who-file ] [ am I ]

     Who, without an argument, lists the name, typewriter chan-
     nel, 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 cre-
     ated.  Then who lists logins, logouts, and crashes since the
     creation of the wtmp file.  Each login is listed with user
     name, typewriter name (with `/dev/' suppressed), and date
     and time.  When an argument is given, logouts produce a sim-
     ilar 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, who behaves as if it had no arguments
     except for restricting the printout to the line for the cur-
     rent typewriter.  Thus `who am I' (and also `who are you')
     tells you who you are logged in as.


     login (I), init (VIII)