WHO(1) User Commands WHO(1)

NAME

who - who is on the system

SYNOPSIS

/usr/bin/who [-abdHlmpqrstTu] [file]


/usr/bin/who -q [-n x] [file]


/usr/bin/who am i


/usr/bin/who am I


/usr/xpg4/bin/who [-abdHlmpqrtTu] [file]


/usr/xpg4/bin/who -q [-n x] [file]


/usr/xpg4/bin/who -s [-bdHlmpqrtu] [file]


/usr/xpg4/bin/who am i


/usr/xpg4/bin/who am I

DESCRIPTION

The who utility 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/utmpx file to obtain its information. If
file is given, that file (which must be in utmpx(5) format) is
examined. Usually, file will be /var/adm/wtmpx, which contains a
history of all the logins since the file was last created.


The general format for output is:

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


where:

name
User's login name


state
Capability of writing to the terminal


line
Name of the line found in /dev


time
Time since user's login


idle
Time elapsed since the user's last activity


pid
User's process id


comment
Comment line in inittab(5)


exit
Exit status for dead processes

OPTIONS

The following options are supported:

-a
Processes /var/adm/utmpx or the named file with -b, -d, -l,
-p, -r, -t, -T, and -u options turned on.


-b
Indicates the time and date of the last reboot.


-d
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 of
the dead process. This can be useful in determining why a
process terminated.


-H
Outputs column headings above the regular output.


-l
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.


-m
Outputs only information about the current terminal.


-n x
Takes a numeric argument, x, which specifies the number of
users to display per line. x must be at least 1. The -n
option can only be used with -q.


-p
Lists any other process that is currently active and has
been previously spawned by init. The name field is the name
of the program executed by init as found in /etc/inittab.
The state, line, and idle fields have no meaning. The
comment field shows the id field of the line from
/etc/inittab that spawned this process. See inittab(5).


-q
(Quick who) Displays only the names and the number of users
currently logged on. When this option is used, all other
options are ignored.


-r
Indicates the current run-level of the init process.


-s
(Default) Lists only the name, line, and time fields.


/usr/bin/who
-T
Same as the -s option, except that the state idle, pid, and
comment, fields are also written. state is one of the
following characters:

+
The terminal allows write access to other users.


-
The terminal denies write access to other users.


?
The terminal write-access state cannot be determined.


/usr/xpg4/bin/who
-T
Same as the -s option, except that the state field is also
written. state is one of the characters listed under the
/usr/bin/who version of this option. If the -u option is used
with -T, the idle time is added to the end of the previous
format.


-t
Indicates the last change to the system clock (using the date
utility) by root. See su(8) and date(1).


-u
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 /etc/inittab (see inittab(5)). This can
contain information about where the terminal is located, the
telephone number of the dataset, type of terminal if hard-
wired, and so forth.

OPERANDS

The following operands are supported:

am i
am I
In the "C" locale, limits the output to describing the
invoking user, equivalent to the -m option. The am and i or
I must be separate arguments.


file
Specifies a path name of a file to substitute for the
database of logged-on users that who uses by default.

ENVIRONMENT VARIABLES

See environ(7) for descriptions of the following environment
variables that affect the execution of who: LANG, LC_ALL, LC_CTYPE,
LC_MESSAGES, LC_TIME, and NLSPATH.

EXIT STATUS

The following exit values are returned:

0
Successful completion.


>0
An error occurred.

FILES

/etc/inittab
Script for init


/var/adm/utmpx
Current user and accounting information


/var/adm/wtmpx
Historic user and accounting information

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:

/usr/xpg4/bin/who

+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+

SEE ALSO

date(1), login(1), mesg(1), inittab(5), utmpx(5), attributes(7),
environ(7), standards(7), init(8), su(8)

NOTES

Superuser: After a shutdown to the single-user state, who returns a
prompt. Since /var/adm/utmpx is updated at login time and there is no
login in single-user state, who cannot report accurately on this
state. The command, who am i, however, returns the correct
information.

August 13, 2023 WHO(1)