login-utils/last.1

.\" Copyright (C) 1998-2004 Miquel van Smoorenburg.
.\"
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.TH "LAST, LASTB" "1" "October 2013" "util-linux" "User Commands"
.SH NAME
last, lastb \- show a listing of last logged in users
.SH SYNOPSIS
.B last
[options]
.RI [ username "...] [" tty ...]
.br
.B lastb
[options]
.RI [ username "...] [" tty ...]
.SH DESCRIPTION
.B last
searches back through the
.B /var/log/wtmp
file (or the file designated by the
.B \-f
option) and displays a list of all users logged in (and out) since that
file was created.  One or more
.IR usernames " and/or " ttys
can be given, in which case
.B last
will show only the entries matching those arguments.  Names of
.I ttys
can be abbreviated, thus
.B last 0
is the same as
.BR "last tty0" .
.PP
When catching a \s-2SIGINT\s0 signal (generated by the interrupt key, usually
control-C) or a \s-2SIGQUIT\s0 signal,
.B last
will show how far it has searched through the file; in the case of the
\s-2SIGINT\s0 signal
.B last
will then terminate.
.PP
The pseudo user
.B reboot
logs in each time the system is rebooted.  Thus
.B last reboot
will show a log of all the reboots since the log file was created.
.PP
.B lastb
is the same as
.BR last ,
except that by default it shows a log of the
.BR /var/log/btmp
file, which contains all the bad login attempts.
.SH OPTIONS
.TP
.BR \-a , " \-\-hostlast"
Display the hostname in the last column.  Useful in combination with the
.B \-\-dns
option.
.TP
.BR \-d , " \-\-dns"
For non-local logins, Linux stores not only the host name of the remote
host, but its IP number as well.  This option translates the IP number
back into a hostname.
.TP
.BR \-f , " \-\-file " \fIfile\fR
Tell
.B last
to use a specific \fIfile\fR instead of
.BR /var/log/wtmp .
The
.B \-\-file
option can be given multiple times, and all of the specified files will be
processed.
.TP
.BR \-F , " \-\-fulltimes"
Print full login and logout times and dates.
.TP
.BR \-i , " \-\-ip"
Like
.B \-\-dns ,
but displays the host's IP number instead of the name.
.TP
.BI \- number
.TQ
.BR \-n , " -\-limit " \fInumber\fR
Tell
.B last
how many lines to show.
.TP
.BR \-p , " \-\-present " \fItime\fR
Display the users who were present at the specified time.  This is
like using the options
.BR \-\-since " and " \-\-until
together with the same \fItime\fR.
.TP
.BR \-R , " \-\-nohostname"
Suppresses the display of the hostname field.
.TP
.BR \-s , " \-\-since " \fItime\fR
Display the state of logins since the specified
.IR time .
This is useful, e.g., to easily determine who was logged in at a
particular time.  The option is often combined with
.BR \-\-until .
.TP
.BR \-t , " \-\-until " \fItime\fR
Display the state of logins until the specified
.IR time .
.TP
.BI \-\-time\-format " format"
Define the output timestamp
.I format
to be one of
.IR notime ,
.IR short ,
.IR full ,
or
.IR iso .
The
.I notime
variant will not print any timestamps at all,
.I short
is the default, and
.I full
is the same as the
.B \-\-fulltimes
option.  The
.I iso
variant will display the timestamp in ISO-8601 format.  The ISO format
contains timezone information, making it preferable when printouts are
investigated outside of the system.
.TP
.BR \-w , " \-\-fullnames"
Display full user names and domain names in the output.
.TP
.BR \-x , " \-\-system"
Display the system shutdown entries and run level changes.
.SH TIME FORMATS
The options that take the
.I time
argument understand the following formats:
.TS
left l2 l.
YYYYMMDDhhmmss
YYYY-MM-DD hh:mm:ss
YYYY-MM-DD hh:mm	(seconds will be set to 00)
YYYY-MM-DD	(time will be set to 00:00:00)
hh:mm:ss	(date will be set to today)
hh:mm	(date will be set to today, seconds to 00)
now
yesterday	(time is set to 00:00:00)
today	(time is set to 00:00:00)
tomorrow	(time is set to 00:00:00)
+5min
-5days
.TE
.SH NOTES
The files
.I wtmp
and
.I btmp
might not be found.  The system only logs information in these files if
they are present.  This is a local configuration issue.  If you want the
files to be used, they can be created with a simple
.BR touch (1)
command (for example,
.IR "touch /var/log/wtmp" ).
.SH FILES
/var/log/wtmp
.br
/var/log/btmp
.SH AUTHOR
.MT miquels@cistron.nl
Miquel van Smoorenburg
.ME
.SH AVAILABILITY
The last command is part of the util-linux package and is available from
.UR ftp://\:ftp.kernel.org\:/pub\:/linux\:/utils\:/util-linux/
Linux Kernel Archive
.UE .
.SH "SEE ALSO"
.BR shutdown (8),
.BR login (1),
.BR init (8)