who(1)							      General Commands Manual							    who(1)

NAME

       who - who is on the system

SYNOPSIS

       [file]

DESCRIPTION

       The  command  can  list the user's name, terminal line, login time, elapsed time since input activity occurred on the line, the user's host
       name, and the process-ID of the command interpreter (shell) for each current system user.  It examines the database to obtain the  informa-
       tion.  If file is given, that file is examined, file should be a like file.

       The command with the or option identifies the invoking user.

       Except for the default option, the general format for output entries is:

	      name [state] line time activity pid [comment] [exit]

       With options, can list logins, logoffs, reboots, and changes to the system clock, as well as other processes spawned by the process.

   Options
	      Output only information about the current terminal.
			     This option is equivalent to the and options described above.

	      Lists only those users who are currently logged in.
			     name  is the user's login name.  line is the name of the line as found in the directory The time field indicates when
			     the user logged in.

			     activity is the number of hours and minutes since input activity last occurred on that particular line.  A dot  indi-
			     cates  that the terminal has seen activity in the last minute and is therefore ``current''.  If more than twenty-four
			     hours have elapsed or the line has not been used since boot time, the entry is marked This field is useful when  try-
			     ing  to  determine whether a person is working at the terminal or not.  The pid is the process-ID of the user's login
			     process.  The comment is the comment field associated with this line as found in (see inittab(4)).  This can  contain
			     information about where the terminal is located, the telephone number of the dataset, type of terminal if hard-wired,
			     etc.  If no such information is found, then prints, as the comment, the user's host name as  it  was  stored  in  the
			     database or named file.  Note that the user's host name is printed instead of comments from the file if the option is
			     used in conjunction with the option.

	      Same as the    option, except that the state of the terminal line is printed.  state describes whether someone  else  can  write	to
			     that terminal.  A appears if the terminal is writable by anyone; a appears if it is not.  can write to all lines hav-
			     ing a or a in the state field.  If a bad line is encountered, a is printed.

			     (UNIX Standard only, see standards(5).)  Only the following fields are displayed: name state line time

	      Lists only those lines
			     on which the system is waiting for someone to login.  The name field is in such cases.  Other fields are the same	as
			     for user entries except that the state field does not exist.

	      Prints column headings above the regular output.

	      A quick	     displaying  only  the names and the number of users currently logged in.  When this option is used, all other options
			     are ignored.

	      Lists any other process which is currently active and has
			     been previously spawned by init.  The name field is the name of the program executed by as found in The state,  line,
			     and  activity  fields  have  no  meaning.	 The  comment  field shows the id field of the line from that spawned this
			     process.  See inittab(4).

	      This option displays all processes
			     that have expired and have not been respawned by The exit field appears for dead processes and contains the  termina-
			     tion  and	exit  values of the dead process (as returned by -- see wait(2)).  This can be useful in determining why a
			     process terminated.

	      Indicates the time and date of the last reboot.

	      Indicates the current
			     run-level of the process.	The last three fields contain the current state of the number of times that state has been
			     previously entered, and the previous state.  These fields are updated each time changes to a different run state.

	      Indicates the last change to the system clock (via the
			     command) by See su(1).

	      Processes      database or the named file with all options turned on.

	      Default.	Lists only the
			     name, line, and time fields.

	      When the	     file  is specified, (the option can be used to examine the file) this option indicates when the accounting system was
			     turned on or off using the or commands (see acctsh(1M)).  The name field is a dot The line field is or a reason  that
			     was given as an option to the command.  The time is the time that the on/off activity occurred.

	      Displays the user's host name.
			     If the user is logged in on a tty, displays the string returned from (see gethostname(2)).  If the user is not logged
			     in on a tty and the host name stored in the database or named like file has not been truncated when  stored  (meaning
			     that  the entire host name was stored with no loss of information), it is displayed as it was stored.  Otherwise, the
			     (IPv4) or (IPv6) function is called with the internet address of  the  host  (see	gethostent(3N)).   The	host  name
			     returned  by  (IPv4) or (IPv6) is displayed unless it returns an error, in which case the truncated host name is dis-
			     played.

	      Gets the information from
			     file.

       (UNIX Standard only, see standards(5).  The option can not be used with or options. If option is used with the idle time is  added  to  the
       end of the format.)

EXTERNAL INFLUENCES

       For information about the UNIX Standard environment, see standards(5).

   Environment Variables
       determines  the locale to use for the locale categories when both and the corresponding environment variable (beginning with do not specify
       a locale.  If is not set or is set to the empty string, a default of "C" (see lang(5)) is used.

       determines the locale for interpretation of sequences of bytes of text data as characters (e.g., single-  verses  multibyte  characters	in
       arguments and input files).

       determines the format and contents of date and time strings.

       determines the language in which messages are displayed.

       If  any	internationalization  variable	contains an invalid setting, behaves as if all internationalization variables are set to "C".  See
       environ(5).

   International Code Set Support
       Single- and multi-byte character code sets are supported.

EXAMPLES

       Check who is logged in on the system:

       Check whether or not you can write to the terminal that another user is using:

       and look for a plus after the user ID.

AUTHOR

       was developed by AT&T and HP.

FILES

SEE ALSO

       date(1), login(1), mesg(1), su(1), init(1M), utmpd(1M), gethostname(2), wait(2), gethostent(3N), getutsent(3C),	getbwent(3C),  inittab(4),
       utmp(4), standards(5).

STANDARDS CONFORMANCE

																	    who(1)