who(1) who(1)
NAME
who - who is on the system
SYNOPSIS
who [-a] [-b] [-d] [-H] [-l] [-p] [-q] [-r] [-s] [-t] [-T]
[-u] [file]
who am i
who am I
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 /etc/utmp file
to obtain its information. If file is given, that file is
examined. Usually, file will be /etc/wtmp, which contains a
history of all the logins since the file was last created.
who with am i or am I added on identifies the invoking user.
Except for the default -s flag option, the general format
for output entries is:
name[ state ] line time activity pid [ comment ] [ exit
]
With flag options, who can list logins, logoffs, reboots,
and changes to the system clock, as well as other processes
spawned by the init process. These flag options are:
-a This flag option processes /etc/utmp or the named file
with all options turned on.
-b This flag option indicates the time and date of the last
reboot.
-d This flag option displays all processes that have
expired and not been respawned by init.
-H This flag option will print column headings above the
regular output.
-l This flag 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.
-p This flag option lists any non-getty process which is
currently active and has been previously spawned by
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who(1) who(1)
init. The name field is the name of the program
executed by init as found in /etc/inittab. The state,
line, and activity fields have no meaning. The comment
field shows the id field of the line from /etc/inittab
that spawned this process. See inittab(4). The exit
field appears for dead processes and contains the
termination and exit values (as returned by wait(2)), of
the dead process. This can be useful in determining why
a process terminated.
-q This is a quick who, displaying only the names and the
number of users currently logged on. When this flag
option is used, all other flag options are ignored.
-r This flag option indicates the current run-level of the
init process.
-s This flag option is the default and lists only the name,
line, time, and remote host (if any) fields.
-t This flag option indicates the last change to the system
clock (via the date(1) command) by root. See su(1).
-T This flag option is the same as the -u flag 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.
-u This flag 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 activity is 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(4)). This can contain information about where
the terminal is located, the telephone number of the
dataset, type of terminal if hard-wired, etc.
EXAMPLE
who am i
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who(1) who(1)
reports the name under which you are currently logged in.
FILES
/bin/who
/etc/utmp
/etc/wtmp
/etc/inittab
SEE ALSO
date(1), login(1), mesg(1), su(1), wait(2), inittab(4),
utmp(4), init(1M).
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