who - display who is logged in
who [-HmqTu] [file]
who am i
The who utility displays a list of all users currently
logged on, showing
for each user the login name, tty name, the date and time of
hostname if not local.
The options are as follows:
-H Write column headings above the regular output.
-m Only print information about the current terminal.
This is the
POSIX way of saying who am i.
-q (Quick.) List only the names and the number of
logged on. When this option is used, all other options are ignored.
-T Print a character after the user name indicating the
state of the
terminal line: `+' if the terminal is writable; `-'
if it is not;
and `?' if a bad line is encountered.
-u Print the idle time for each user.
am I Returns the invoker's real user name.
file By default, who gathers information from the file
An alternate file may be specified which is usually
(or /var/log/wtmp.[0-6] depending on site policy as
wtmp can grow
quite large and daily versions may or may not be
kept around after
compression by ac(8)). The wtmp file contains a
every login, logout, crash, shutdown and date change
was last truncated or created.
If /var/log/wtmp is being used as the file, the user name
may be empty or
one of the special characters `|', `}', and `~'. Logouts
produce an output
line without any user name. For more information on the
characters, see utmp(5).
last(1), mesg(1), users(1), w(1), getuid(2), utmp(5)
The who utility is expected to conform to IEEE Std
A who utility appeared in Version 3 AT&T UNIX.
OpenBSD 3.6 December 6, 1994
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