|
» |
|
|
|
NAMEwho — who is on the system SYNOPSISwho
[-muTlHqpdbrtasARW]
[file] who am i who am I DESCRIPTIONThe
who
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
utmps
database
to obtain the information.
If
file
is given, that file is examined,
file
should be a
utmp
like file. The
who
command with the
am i
or
am I
option identifies the invoking user. Except for the default
-s
option, the general format for output entries is:
name [state] line time activity pid [comment] [exit]
With options,
who
can list logins, logoffs, reboots, and changes to the system clock,
as well as other processes spawned by the
init
process. Options- -m
Output only information about the current terminal.
This option is equivalent to the
am i
and
am I
options described above. - -u
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
/dev.
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
(.)
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 login process.
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.
If no such information is found, then
who
prints, as the
comment,
the user's host name as it was stored in the
utmps
database
or named
file.
Note that the user's host name is printed instead of comments from the
/etc/inittab
file if the
-u
option is used in conjunction with the
-R
option. - -T
Same as the
-u
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.
root
can write to all lines having 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 - -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. - -H
Prints column headings above the regular output. - -q
A quick
who,
displaying only the names and the number of users currently logged in.
When this option is used, all other options are ignored. - -p
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
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). - -d
This option displays all processes
that have expired and have not been respawned by
init.
The
exit
field appears for dead processes and contains the termination and exit
values of the dead process (as returned by
wait()
— see
wait(2)).
This can be useful in determining why a process terminated. - -b
Indicates the time and date of the last reboot. - -r
Indicates the current
run-level
of the
init
process.
The last three fields contain the current state of
init,
the number of times that state has been previously entered,
and the previous state.
These fields are updated each time
init
changes to a different run state. - -t
Indicates the last change to the system clock (via the
date
command) by
root.
See
su(1). - -a
Processes
utmps
database or the named
file
with all options turned on. - -s
Default. Lists only the
name,
line,
and
time
fields. - -A
When the
/var/adm/wtmp
file is specified, (the
-W
option can be used to examine the
/var/adm/wtmps
file) this option indicates when the accounting system
was turned on or off using the
startup
or
shutacct
commands (see
acctsh(1M)).
The
name
field is a dot
(.).
The
line
field is
acctg on,
acctg off,
or a reason that was given as an option to the
shutacct
command.
The
time
is the time that the on/off activity occurred. - -R
Displays the user's host name.
If the user is logged in on a tty,
who
displays the string returned from
gethostname()
(see
gethostname(2)).
If the user is not logged in on a tty
and the host name stored in the
utmps
database
or named
utmp
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
gethostbyaddr()
(IPv4) or
getipnodebyaddr()
(IPv6)
function is called with the internet address of the host (see
gethostent(3N)).
The host name returned by
gethostbyaddr()
(IPv4) or
getipnodebyaddr()
(IPv6)
is displayed unless it returns an error,
in which case the truncated host name is displayed. - -W
Gets the information from
/var/adm/wtmps
file.
(UNIX Standard only, see
standards(5).
The
-s
option can not be used with
-d,
-a
or
-T
options. If
-u
option is used with
-T,
the idle time is added to the end of the
-T
format.) EXTERNAL INFLUENCESFor information about the UNIX Standard environment, see
standards(5). Environment VariablesLANG
determines the locale to use for the locale categories when both
LC_ALL
and the corresponding environment variable (beginning with
LC_)
do not specify a locale.
If
LANG
is not set or is set to the empty string, a default of "C" (see
lang(5))
is used. LC_CTYPE
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). LC_TIME
determines the format and contents of date and time strings. LC_MESSAGES
determines the language in which messages are displayed. If any internationalization variable contains an invalid setting,
who
behaves as if all internationalization variables are set to "C".
See
environ(5). International Code Set SupportSingle- and multi-byte character code sets are supported. EXAMPLESCheck 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. AUTHORwho
was developed by AT&T and HP. FILES/etc/inittab
/etc/utmp
/var/adm/wtmp
/var/adm/wtmps SEE ALSOdate(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 CONFORMANCEwho: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2
|