1.\" Copyright (c) 1980, 1990 Regents of the University of California. 2.\" All rights reserved. The Berkeley software License Agreement 3.\" specifies the terms and conditions for redistribution. 4.\" 5.\" @(#)login.1 6.9 (Berkeley) 03/14/91 6.\" 7.Vx 8.Vx 9.Dd 10.Dt LOGIN 1 11.Os BSD 4 12.Sh NAME 13.Nm login 14.Nd sign on 15.Sh SYNOPSIS 16.Nm login 17.Op Fl p 18.Op Ar username 19.Nm login 20.Op Fl p 21.Op Fl h Ar hostname 22.Op Fl f 23.Op Ar username 24.Sh DESCRIPTION 25The 26.Nm login 27command 28is used when a user initially 29signs on. 30It may also be used at any time to change 31from one user to another. 32This case is the one summarized first above and described here. 33See 34.Em How to Get Started 35for how to connect initially. 36The invocation of 37.Nm login 38for initial sign-on 39is made by a system program or server using the latter form of the command 40and is described below. 41.Pp 42If 43.Nm login 44is invoked without an argument, 45it asks for a user name, and, if 46appropriate, a password. 47Echoing is turned off (if possible) during the typing of the password, 48so it will not appear on the written record of the 49session. 50.Pp 51After a successful login, 52accounting files are updated and 53the user is informed of the 54existence of mail. 55The message of the day is printed, 56as is the time of his last login. 57Both are suppressed if he has a 58.Dq Pa .hushlogin 59file in his home directory; this 60is mostly used to make life easier for non-human users, such as 61.Xr uucp 1 . 62.Pp 63.Nm Login 64initializes the user and group IDs and the working directory, 65then executes a command interpreter (usually 66.Xr csh 1 ) 67according to specifications found in a password file. 68Argument 0 of the command interpreter is 69the name of the command interpreter with 70a leading dash 71.Sq Fl . 72.Pp 73Login also modifies the 74environment (see 75.Xr environ 7 ) 76with information specifying home directory, command interpreter, terminal 77type (if available) and user name. 78.Pp 79Options: 80.Pp 81.Tw Ds 82.Tp Fl p 83Causes the remainder of the environment to be preserved, 84otherwise any previous environment is discarded. 85.Tp Fl h 86option is used by 87.Xr telnetd 8 88(at initial login) 89and other servers to list the host from which 90the connection was received. 91.Tp Fl f 92Used with a username on the command line, at initial login, 93to indicate that proper authentication has already been done 94and that no password need be requested. 95This option may be used by the superuser 96or by the user specified on the command line. 97.Tp 98.Pp 99If the file 100.Pa /etc/nologin 101exists, 102.Nm login 103prints its contents on the user's terminal and exits. This is 104used by 105.Xr shutdown 8 106to stop users logging in when the system is about to go down. 107.Pp 108Login is recognized by 109.Xr sh 1 110and 111.Xr csh 1 112and executed directly (without forking). 113.Sh FILES 114.Dw /var/log/wtmp 115.Di L 116.Dp Pa /var/run/utmp 117accounting 118.Dp Pa /var/log/wtmp 119accounting 120.Dp Pa /var/mail/* 121mail 122.Dp Pa /etc/motd 123message-of-the-day 124.Dp Pa /etc/passwd 125password file 126.Dp Pa /etc/nologin 127stops logins 128.Dp Pa \&.hushlogin 129makes login quieter 130.Dp 131.Sh SEE ALSO 132.Xr mail 1 , 133.Xr passwd 1 , 134.Xr rlogin 1 , 135.Xr getpass 3 , 136.Xr passwd 5 , 137.Xr utmp 5 , 138.Xr environ 7 , 139.Xr init 8 , 140.Xr getty 8 , 141.Xr shutdown 8 , 142.Sh HISTORY 143.Nm login 144appeared in Version 6 AT&T Unix. 145.Sh DIAGNOSTICS 146.Dw Fl 147.Di L 148.Dp Li Login incorrect 149if the name or the password is bad. 150.Dp Li No Shell 151.Dp Li cannot open password file 152.Dp Li no directory 153consult a programming counselor. 154.Dp 155