.TH LOGIN 1 .SH NAMElogin  \-  sign on.SH SYNOPSIS.B login[ username ].SH DESCRIPTIONThe.I logincommandis used when a user initiallysigns on, or it may be used at any time to changefrom one user to another.The latter case is the one summarized above anddescribed here.See `How to Get Started' for how to dial up initially..PPIf.I loginis invoked without an argument,it asks for a user name, and, ifappropriate, a password.Echoing is turned off (if possible) during the typing of the password,so it will not appear on the written record of thesession..PPAfter a successful login,accounting files are updated andthe user is informed of theexistence of.I .mailand message-of-the-day files..I Logininitializes the user and group IDs and the working directory,then executes a command interpreter (usually.IR  sh (1))according to specifications found in a password file.Argument 0 of the command interpreter is `\-sh..PPLogin is recognized by.IR sh (1)and executed directly (without forking)..SH FILES.ta \w'/usr/adm/wtmp\ \ 'u/etc/utmp	accounting.br/usr/adm/wtmp	accounting.br/usr/mail/*	mail.br/etc/motd	message-of-the-day.br/etc/passwd	password file.SH "SEE ALSO"init(8), newgrp(1), getty(8), mail(1), passwd(1), passwd(5).SH DIAGNOSTICS`Login incorrect,'if the name or the password is bad..br`No Shell', `cannot open password file', `no directory':consult a programming counselor.