who(1) [bsd man page]

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 /var/run/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

       /var/run/utmp

SEE ALSO

       getuid(2), utmp(5)

7th Edition							 November 27, 1996							    WHO(1)

UTMP(5) 							File Formats Manual							   UTMP(5)

NAME

       utmp, wtmp - logged in users, login and logout history

SYNOPSIS

       #include <sys/types.h>
       #include <utmp.h>

DESCRIPTION

       The files /etc/utmp and /usr/adm/wtmp respectively contain the currently logged in users, and the history of logins and logouts.

       Each file is an array of the following structure defined in <utmp.h>:

       struct utmp {
	    char	   ut_user[8];	  /* user name */
	    char	   ut_line[12];   /* terminal name */
	    char	   ut_host[16];   /* host name, when remote */
	    time_t	   ut_time;	  /* login/logout time */
       };

       #define ut_name ut_user/* for compatibility with other systems */

       The  structure  contains  more fields than those listed, but they are only of interest to init and login.  Note that the ut_name field is a
       compatibility alias for ut_user, it is actually better to use it.

       A login entry is completely specified.  A logout entry has a null string for ut_name.  A shutdown or reboot entry has an ut_line field con-
       taining	a  "~" (tilde).  The ut_name field is usually the name of the program that did the shutdown, or "reboot" at reboot.  This is a bit
       confusing, but note that there should always be two such entries.  If you see just one entry then the system has crashed, if  you  see  two
       entries then the system was properly shut down and later rebooted.

FILES

       /etc/utmp		Currently logged in users.

       /usr/adm/wtmp		History of logins and logouts.

SEE ALSO

       who(1), ttyslot(3).

AUTHOR

       Kees J. Bot (kjb@cs.vu.nl)

																	   UTMP(5)