'\" t
.\"     Title: login
.\"    Author: Julianne Frances Haugh
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\"      Date: 07/02/2020
.\"    Manual: Comandi utente
.\"    Source: shadow-utils 4.8.1
.\"  Language: Italian
.\"
.TH "LOGIN" "1" "07/02/2020" "shadow\-utils 4\&.8\&.1" "Comandi utente"
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.SH "NOME"
login \- apre una sessione sul sistema
.SH "SINOSSI"
.HP \w'\fBlogin\fR\ 'u
\fBlogin\fR [\-p] [\-h\ \fIhost\fR] [\fInome\fR] [\fIENV=VAR\fR...]
.HP \w'\fBlogin\fR\ 'u
\fBlogin\fR [\-p] [\-h\ \fIhost\fR] \-f \fInome\fR
.HP \w'\fBlogin\fR\ 'u
\fBlogin\fR [\-p] \-r\ \fIhost\fR
.SH "DESCRIZIONE"
.PP
The
\fBlogin\fR
program is used to establish a new session with the system\&. It is normally invoked automatically by responding to the
\fIlogin:\fR
prompt on the user\*(Aqs terminal\&.
\fBlogin\fR
may be special to the shell and may not be invoked as a sub\-process\&. When called from a shell,
\fBlogin\fR
should be executed as
\fBexec login\fR
which will cause the user to exit from the current shell (and thus will prevent the new logged in user to return to the session of the caller)\&. Attempting to execute
\fBlogin\fR
from any shell but the login shell will produce an error message\&.
.PP
The user is then prompted for a password, where appropriate\&. Echoing is disabled to prevent revealing the password\&. Only a small number of password failures are permitted before
\fBlogin\fR
exits and the communications link is severed\&.
.PP
If password aging has been enabled for your account, you may be prompted for a new password before proceeding\&. You will be forced to provide your old password and the new password before continuing\&. Please refer to
\fBpasswd\fR(1)
for more information\&.
.PP
Your user and group ID will be set according to their values in the
/etc/passwd
file\&. The value for
\fB$HOME\fR,
\fB$SHELL\fR,
\fB$PATH\fR,
\fB$LOGNAME\fR, and
\fB$MAIL\fR
are set according to the appropriate fields in the password entry\&. Ulimit, umask and nice values may also be set according to entries in the GECOS field\&.
.PP
On some installations, the environmental variable
\fB$TERM\fR
will be initialized to the terminal type on your tty line, as specified in
/etc/ttytype\&.
.PP
Pu\(`o anche essere eseguito uno script di inizializzazione per il proprio interprete dei comandi\&. Fare riferimento alla relativa sezione di manuale per maggiori informazioni su questa funzione\&.
.PP
Un sottosistema di login \(`e indicato dalla presenza del carattere \(Fo*\(Fc all\*(Aqinizio della shell di login\&. La directory home impostata sar\(`a utilizzata come root di un nuovo file system al quale l\*(Aqutente accede\&.
.PP
The
\fBlogin\fR
program is NOT responsible for removing users from the utmp file\&. It is the responsibility of
\fBgetty\fR(8)
and
\fBinit\fR(8)
to clean up apparent ownership of a terminal session\&. If you use
\fBlogin\fR
from the shell prompt without
\fBexec\fR, the user you use will continue to appear to be logged in even after you log out of the "subsession"\&.
.SH "OPZIONI"
.PP
\fB\-f\fR
.RS 4
Non effettua l\*(Aqautenticazione, l\*(Aqutente \(`e gi\(`a autenticato
.sp
Note: In that case,
\fIusername\fR
is mandatory\&.
.RE
.PP
\fB\-h\fR
.RS 4
Nome dell\*(Aqhost remoto per questo login\&.
.RE
.PP
\fB\-p\fR
.RS 4
Non modifica l\*(Aqambiente\&.
.RE
.PP
\fB\-r\fR
.RS 4
Attiva il protocollo autologin di rlogin\&.
.RE
.PP
The
\fB\-r\fR,
\fB\-h\fR
and
\fB\-f\fR
options are only used when
\fBlogin\fR
is invoked by root\&.
.SH "AVVISI/CAVEAT"
.PP
This version of
\fBlogin\fR
has many compilation options, only some of which may be in use at any particular site\&.
.PP
La posizione dei file \(`e soggetta a differenze in base alla configurazione del sistema\&.
.PP
The
\fBlogin\fR
program is NOT responsible for removing users from the utmp file\&. It is the responsibility of
\fBgetty\fR(8)
and
\fBinit\fR(8)
to clean up apparent ownership of a terminal session\&. If you use
\fBlogin\fR
from the shell prompt without
\fBexec\fR, the user you use will continue to appear to be logged in even after you log out of the "subsession"\&.
.PP
As with any program,
\fBlogin\fR\*(Aqs appearance can be faked\&. If non\-trusted users have physical access to a machine, an attacker could use this to obtain the password of the next person coming to sit in front of the machine\&. Under Linux, the SAK mechanism can be used by users to initiate a trusted path and prevent this kind of attack\&.
.SH "CONFIGURAZIONE"
.PP
The following configuration variables in
/etc/login\&.defs
change the behavior of this tool:
.PP
\fBCONSOLE_GROUPS\fR (string)
.RS 4
List of groups to add to the user\*(Aqs supplementary groups set when logging in on the console (as determined by the CONSOLE setting)\&. Default is none\&.

Use with caution \- it is possible for users to gain permanent access to these groups, even when not logged in on the console\&.
.RE
.PP
\fBDEFAULT_HOME\fR (boolean)
.RS 4
Indica se permettere l\*(Aqaccesso al sistema anche se non si pu\(`o accedere alla directory home\&. Il valore predefinito \(`e no\&.
.sp
If set to
\fIyes\fR, the user will login in the root (/) directory if it is not possible to cd to her home directory\&.
.RE
.PP
\fBENV_PATH\fR (string)
.RS 4
If set, it will be used to define the PATH environment variable when a regular user login\&. The value is a colon separated list of paths (for example
\fI/bin:/usr/bin\fR) and can be preceded by
\fIPATH=\fR\&. The default value is
\fIPATH=/bin:/usr/bin\fR\&.
.RE
.PP
\fBENV_SUPATH\fR (string)
.RS 4
If set, it will be used to define the PATH environment variable when the superuser login\&. The value is a colon separated list of paths (for example
\fI/sbin:/bin:/usr/sbin:/usr/bin\fR) and can be preceded by
\fIPATH=\fR\&. The default value is
\fIPATH=/sbin:/bin:/usr/sbin:/usr/bin\fR\&.
.RE
.PP
\fBERASECHAR\fR (number)
.RS 4
Terminal ERASE character (\fI010\fR
= backspace,
\fI0177\fR
= DEL)\&.
.sp
Il valore deve avere il prefisso \(Fo0\(Fc se in ottale, o \(Fo0x\(Fc se esadecimale\&.
.RE
.PP
\fBFAIL_DELAY\fR (number)
.RS 4
Numero di secondi prima che venga concesso un ulteriore tentativo dopo un accesso fallito\&.
.RE
.PP
\fBFAKE_SHELL\fR (string)
.RS 4
If set,
\fBlogin\fR
will execute this shell instead of the users\*(Aq shell specified in
/etc/passwd\&.
.RE
.PP
\fBHUSHLOGIN_FILE\fR (string)
.RS 4
Se definito, questo file inibisce quanto stampato durante l\*(Aqaccesso\&. Se viene specificato un percorso completo, la modalit\(`a silenziosa (hushed) viene attivata se in quel file \(`e presente il nome dell\*(Aqutente o della shell dell\*(Aqutente\&. Se il percorso non \(`e completo, allora la modalit\(`a silenziosa viene attivata se quel file \(`e presente nella directory home dell\*(Aqutente\&.
.RE
.PP
\fBKILLCHAR\fR (number)
.RS 4
Terminal KILL character (\fI025\fR
= CTRL/U)\&.
.sp
Il valore deve avere il prefisso \(Fo0\(Fc se in ottale, o \(Fo0x\(Fc se esadecimale\&.
.RE
.PP
\fBLOGIN_RETRIES\fR (number)
.RS 4
Massimo numero di tentativi di accesso per password errata\&.
.sp
Questa impostazione verr\(`a probabilmente superata da quella di PAM poich\('e il modulo predefinito pam_unix ha una sua gestione con 3 tentativi\&. In ogni caso questa \(`e una impostazione di sicurezza nel caso in cui si utilizzi un modulo PAM che ignora PAM_MAXTRIES\&.
.RE
.PP
\fBLOGIN_TIMEOUT\fR (number)
.RS 4
Numero massimo di secondi per l\*(Aqaccesso\&.
.RE
.PP
\fBLOG_OK_LOGINS\fR (boolean)
.RS 4
Abilita la tracciatura degli accessi avvenuti con successo\&.
.RE
.PP
\fBLOG_UNKFAIL_ENAB\fR (boolean)
.RS 4
Abilita l\*(Aqinclusione dei nomi utente sconosciuti quando si registrano gli accessi falliti\&.
.sp
Nota: memorizzare i nomi sconosciuti potrebbe diventare un problema legato alla sicurezza se un utente inserisce la propria password al posto del nome utente\&.
.RE
.PP
\fBTTYGROUP\fR (string), \fBTTYPERM\fR (string)
.RS 4
The terminal permissions: the login tty will be owned by the
\fBTTYGROUP\fR
group, and the permissions will be set to
\fBTTYPERM\fR\&.
.sp
By default, the ownership of the terminal is set to the user\*(Aqs primary group and the permissions are set to
\fI0600\fR\&.
.sp
\fBTTYGROUP\fR
can be either the name of a group or a numeric group identifier\&.
.sp
If you have a
\fBwrite\fR
program which is "setgid" to a special group which owns the terminals, define TTYGROUP to the group number and TTYPERM to 0620\&. Otherwise leave TTYGROUP commented out and assign TTYPERM to either 622 or 600\&.
.RE
.PP
\fBTTYTYPE_FILE\fR (string)
.RS 4
Se definito si tratta di un file che mappa le linee tty nella variabile d\*(Aqambiente TERM\&. Ogni riga del file \(`e in un formato tipo \(Fovt100 tty01\(Fc\&.
.RE
.PP
\fBUSERGROUPS_ENAB\fR (boolean)
.RS 4
If set to
\fIyes\fR,
\fBuserdel\fR
will remove the user\*(Aqs group if it contains no more members, and
\fBuseradd\fR
will create by default a group with the name of the user\&.
.RE
.SH "FILE"
.PP
/var/run/utmp
.RS 4
Elenco delle sessioni attive\&.
.RE
.PP
/var/log/wtmp
.RS 4
Elenco delle precedenti sessioni di login\&.
.RE
.PP
/etc/passwd
.RS 4
Informazioni sugli account utente\&.
.RE
.PP
/etc/shadow
.RS 4
Informazioni sicure sugli account utente\&.
.RE
.PP
/etc/motd
.RS 4
File di sistema con il messaggio del giorno\&.
.RE
.PP
/etc/nologin
.RS 4
Impedisce l\*(Aqaccesso al sistema per utenti diversi da root\&.
.RE
.PP
/etc/ttytype
.RS 4
Elenco di tipi di terminale\&.
.RE
.PP
$HOME/\&.hushlogin
.RS 4
Impedisce che vengano mostrati i messaggi di sistema\&.
.RE
.PP
/etc/login\&.defs
.RS 4
Configurazione del pacchetto password shadow
.RE
.SH "VEDERE ANCHE"
.PP
\fBmail\fR(1),
\fBpasswd\fR(1),
\fBsh\fR(1),
\fBsu\fR(1),
\fBlogin.defs\fR(5),
\fBnologin\fR(5),
\fBpasswd\fR(5),
\fBsecuretty\fR(5),
\fBgetty\fR(8)\&.