NAME
who - who is on the system
SYNOPSIS
who [ -uTlHqpdbrtas ] [ filename ]
who -qn x [ filename ]
who am i
who am I
AVAILABILITY
SUNWcsu
DESCRIPTION
who can list the user's name, terminal line, login time,
elapsed time since activity occurred on the line, and the
process-ID of the command interpreter (shell) for each
current UNIX system user. It examines the /var/adm/utmp
file to obtain its information. If filename is given, that
file (which must be in utmp(4) format) is examined. Usu-
ally, filename will be /var/adm/wtmp, which contains a his-
tory of all the logins since the file was last created.
who with the am i or am I option identifies the invoking
user.
The general format for output is:
name [state] line time [idle] [pid] [comment] [exit]
The name, line, and time information is produced by all
options except -q; the state information is produced only by
-T; the idle and pid information is produced only by -u and
-l; and the comment and exit information is produced only by
-a. The information produced for - p, - d, and - r is
explained during the discussion of each option, below.
OPTIONS
With options, who can list logins, logoffs, reboots, and
changes to the system clock, as well as other processes
spawned by the init process. These options are:
-u This option lists only those users who are
currently logged in. The name is the user's login
name. The line is the name of the line as found
in the directory /dev . The time is the time that
the user logged in. The idle column contains the
number of hours and minutes since activity last
occurred on that particular line. A dot (.)
indicates 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 old. This field is useful when trying
to determine whether a person is working at the
terminal or not. The pid is the process-ID of the
user's shell. The comment is the comment field
associated with this line as found in
/sbin/inittab (see inittab(4)). This can contain
information about where the terminal is located,
the telephone number of the dataset, type of ter-
minal if hard-wired, and so forth.
-T This option is the same as the -s option, except
that the state of the terminal line is printed.
The 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. root can write to all lines having a ` + '
or a ` - ' in the state field. If a bad line is
encountered, a ` ? ' is printed.
-l This option lists only those lines on which the
system is waiting for someone to login. The name
field is LOGIN in such cases. Other fields are
the same as for user entries except that the state
field does not exist.
-H This option will print column headings above the
regular output.
-q This is a quick who , displaying only the names
and the number of users currently logged on. When
this option is used, all other options are
ignored.
-p This option lists any other process which is
currently active and has been previously spawned
by init . The name field is the name of the pro-
gram executed by init as found in /sbin/inittab.
The state, line, and idle fields have no meaning.
The comment field shows the id field of the line
from /sbin/inittab that spawned this process. See
inittab(4).
-d This option displays all processes that have
expired and not been respawned by init . The exit
field appears for dead processes and contains the
termination and exit values (as returned by
wait(3B)), of the dead process. This can be use-
ful in determining why a process terminated.
-b This option indicates the time and date of the
last reboot.
-r This option indicates the current run-level of
the init process. In addition, it produces the
process termination status, process id, and pro-
cess exit status (see utmp(4)) under the idle,
pid, and comment headings, respectively.
-t This option indicates the last change to the sys-
tem clock (via the date command) by root . See
su(1M) and date(1).
-a This option processes /var/adm/utmp or the named
filename with all options turned on.
-s This option is the default and lists only the
name, line, and time fields.
-nx This option takes a numeric argument, x, which
specifies the number of users to display per line.
x must be at least 1. The -n option must be used
with -q.
Note to the super-user: after a shutdown to the single-user
state, who returns a prompt; the reason is that since
/var/adm/utmp is updated at login time and there is no login
in single-user state, who cannot report accurately on this
state. who am i , however, returns the correct information.
ENVIRONMENT
If any of the LC_* variables ( LC_CTYPE, LC_MESSAGES,
LC_TIME, LC_COLLATE, LC_NUMERIC, and LC_MONETARY ) (see
environ(5)) are not set in the environment, the operational
behavior of who for each corresponding locale category is
determined by the value of the LANG environment variable.
If LC_ALL is set, its contents are used to override both the
LANG and the other LC_* variables. If none of the above
variables is set in the environment, the "C" (U.S. style)
locale determines how who behaves.
LC_CTYPE
Determines how who handles characters. When LC_CTYPE is
set to a valid value, who can display and handle text
and filenames containing valid characters for that
locale. who can display and handle Extended Unix Code
(EUC) characters where any individual character can be
1, 2, or 3 bytes wide. who can also handle EUC charac-
ters of 1, 2, or more column widths. In the "C" locale,
only characters from ISO 8859-1 are valid.
LC_TIME
Determines how who handles date and time formats. In
the "C" locale, date and time handling follows the U.S.
rules.
FILES
/sbin/inittab
/var/adm/utmp
/var/adm/wtmp
SEE ALSO
date(1), login(1), mesg(1), init(1M), su(1M), wait(3B),
inittab(4), utmp(4), environ(5)