usr.bin/last/last.1

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.Dd January 9, 2021
.Dt LAST 1
.Os
.Sh NAME
.Nm last
.Nd indicate last logins of users and ttys
.Sh SYNOPSIS
.Nm
.Op Fl -libxo
.Op Fl swy
.Oo
.Fl d
.Sm off
.Op Oo Ar CC Oc Ar YY
.Op Ar MM DD
.Ar hh mm
.Op Ar .SS
.Sm on
.Oc
.Op Fl f Ar file
.Op Fl h Ar host
.Op Fl n Ar maxrec
.Op Fl t Ar tty
.Op Ar user ...
.Sh DESCRIPTION
The
.Nm
utility will either list the sessions of specified
.Ar users ,
.Ar ttys ,
and
.Ar hosts ,
in reverse time order,
or list the users logged in at a specified date and time.
Each line of output contains
the user name, the tty from which the session was conducted, any
hostname, the start and stop times for the session, and the duration
of the session.
If the session is still continuing or was cut short by
a crash or shutdown,
.Nm
will so indicate.
.Pp
The following options are available:
.Bl -tag -width indent-two
.It Fl -libxo
Generate output via
.Xr libxo 3
in a selection of different human and machine readable formats.
See
.Xr xo_parse_args 3
for details on command line arguments.
.It Fl d Ar date
Specify the snapshot date and time.
All users logged in at the snapshot date and time will
be reported.
This may be used with the
.Fl f
option to derive the results from stored
.Pa utx.log
files.
When this argument is provided, all other options except for
.Fl f
and
.Fl n
are ignored.
The argument should be in the form
.Sm off
.Op Oo Ar CC Oc Ar YY
.Op Ar MM DD
.Ar hh mm
.Op Ar .SS
.Sm on
where each pair of letters represents the following:
.Pp
.Bl -tag -width Ds -compact -offset indent
.It Ar CC
The first two digits of the year (the century).
.It Ar YY
The second two digits of the year.
If
.Ar YY
is specified, but
.Ar CC
is not, a value for
.Ar YY
between 69 and 99 results in a
.Ar CC
value of 19.
Otherwise, a
.Ar CC
value of 20 is used.
.It Ar MM
Month of the year, from 1 to 12.
.It Ar DD
Day of the month, from 1 to 31.
.It Ar hh
Hour of the day, from 0 to 23.
.It Ar mm
Minute of the hour, from 0 to 59.
.It Ar SS
Second of the minute, from 0 to 60.
.El
.Pp
If the
.Ar CC
and
.Ar YY
letter pairs are not specified, the values default to the current
year.
If the
.Ar SS
letter pair is not specified, the value defaults to 0.
.It Fl f Ar file
Read the file
.Ar file
instead of the default,
.Pa /var/log/utx.log .
.It Fl h Ar host
.Ar Host
names may be names or internet numbers.
.It Fl n Ar maxrec
Limit the report to
.Ar maxrec
lines.
.It Fl s
Report the duration of the login session in seconds, instead of the
default days, hours and minutes.
.It Fl t Ar tty
Specify the
.Ar tty .
Tty names may be given fully or abbreviated, for example,
.Dq Li "last -t 03"
is
equivalent to
.Dq Li "last -t tty03" .
.It Fl w
Widen the duration field to show seconds, as well as the
default days, hours and minutes.
.It Fl y
Report the year in the session start time.
.El
.Pp
If multiple arguments are given,
and a snapshot time is not specified,
the information which applies to any of the
arguments is printed, e.g.,
.Dq Li "last root -t console"
would list all of
.Dq Li root Ns 's
sessions as well as all sessions on the console terminal.
If no
users, hostnames or terminals are specified,
.Nm
prints a record of
all logins and logouts.
.Pp
The pseudo-user
.Ar reboot
logs in at reboots of the system, thus
.Dq Li last reboot
will give an indication of mean time between reboot.
.Pp
If
.Nm
is interrupted, it indicates to what date the search has
progressed.
If interrupted with a quit signal
.Nm
indicates how
far the search has progressed and then continues.
.Sh FILES
.Bl -tag -width /var/log/utx.log -compact
.It Pa /var/log/utx.log
login data base
.El
.Sh EXAMPLES
Show logins in pts/14 with the duration in seconds and limit the report to
two lines:
.Bd -literal -offset indent
$ last -n2 -s -t pts/14
bob    pts/1   Wed Dec  9 11:08   still logged in
bob    pts/2   Mon Dec  7 20:10 - 20:23  (     776)
.Ed
.Pp
Show active logins at
.Ql December 7th 20:23
of the current year:
.Bd -literal -offset indent
$ last -d 12072023
bob    pts/1    Mon Dec  7 20:10 - 20:23  (00:12)
bob    pts/6    Mon Dec  7 19:24 - 22:27  (03:03)
alice  ttyv0    Mon Dec  7 19:18 - 22:27  (03:09)
.Ed
.Sh SEE ALSO
.Xr lastcomm 1 ,
.Xr getutxent 3 ,
.Xr libxo 3 ,
.Xr xo_parse_args 3 ,
.Xr ac 8 ,
.Xr lastlogin 8
.Sh HISTORY
.Nm
utility first appeared in
.Bx 1 .
.Sh AUTHORS
.An -nosplit
The original version was written by
.An Howard P. Katseff ;
.An Keith Bostic
rewrote it in 1986/87 to add functionality and to improve code quality.
.An Philip Paeps
added
.Xr libxo 3
support in August 2018.
.Sh BUGS
If a login shell should terminate abnormally for some reason, it is likely
that a logout record will not be written to the
.Pa utx.log
file.
In this case,
.Nm
will indicate the logout time as "shutdown".