449 lines
12 KiB
Groff
449 lines
12 KiB
Groff
'\" t
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.\" Title: su
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.\" Author: Julianne Frances Haugh
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.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
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.\" Date: 23/01/2020
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.\" Manual: Comandi utente
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.\" Source: shadow-utils 4.8.1
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.\" Language: Italian
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.\"
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.TH "SU" "1" "23/01/2020" "shadow\-utils 4\&.8\&.1" "Comandi utente"
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.\" -----------------------------------------------------------------
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.\" * Define some portability stuff
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.\" -----------------------------------------------------------------
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.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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.\" http://bugs.debian.org/507673
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.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
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.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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.ie \n(.g .ds Aq \(aq
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.el .ds Aq '
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.\" -----------------------------------------------------------------
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.\" * set default formatting
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.\" -----------------------------------------------------------------
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.\" disable hyphenation
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.nh
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.\" disable justification (adjust text to left margin only)
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.ad l
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.\" -----------------------------------------------------------------
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.\" * MAIN CONTENT STARTS HERE *
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.\" -----------------------------------------------------------------
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.SH "NOME"
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su \- cambia ID utente o diventa amministratore
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.SH "SINOSSI"
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.HP \w'\fBsu\fR\ 'u
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\fBsu\fR [\fIopzioni\fR] [\fI\-\fR] [\fInome\fR\ [\ \fIargs\fR\ ]]
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.SH "DESCRIZIONE"
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.PP
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The
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\fBsu\fR
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command is used to become another user during a login session\&. Invoked without a
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\fBusername\fR,
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\fBsu\fR
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defaults to becoming the superuser\&. The
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\fB\-\fR
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option may be used to provide an environment similar to what the user would expect had the user logged in directly\&. The
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\fB\-c\fR
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option may be used to treat the next argument as a command by most shells\&.
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.PP
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Options are recognized everywhere in the argument list\&. You can use the
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\fB\-\-\fR
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argument to stop option parsing\&. The
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\fB\-\fR
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option is special: it is also recognized after
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\fB\-\-\fR, but has to be placed before
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\fBusername\fR\&.
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.PP
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All\*(Aqutente viene quindi chiesta la password, se necessario\&. Una password errata viene segnalata da un messaggio d\*(Aqerrore\&. Viene effettuato il log di tutti i tentativi, siano essi riusciti o meno, al fine di rilevare ogni abuso del sistema\&.
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.PP
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The current environment is passed to the new shell\&. The value of
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\fB$PATH\fR
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is reset to
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/bin:/usr/bin
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for normal users, or
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/sbin:/bin:/usr/sbin:/usr/bin
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for the superuser\&. This may be changed with the
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\fBENV_PATH\fR
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and
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\fBENV_SUPATH\fR
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definitions in
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/etc/login\&.defs\&.
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.PP
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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\&.
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.SH "OPZIONI"
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.PP
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The options which apply to the
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\fBsu\fR
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command are:
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.PP
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\fB\-c\fR, \fB\-\-command\fR\ \&\fICOMMAND\fR
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.RS 4
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Specify a command that will be invoked by the shell using its
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\fB\-c\fR\&.
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.sp
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The executed command will have no controlling terminal\&. This option cannot be used to execute interactive programs which need a controlling TTY\&.
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.RE
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.PP
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\fB\-\fR, \fB\-l\fR, \fB\-\-login\fR
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.RS 4
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Fornisce un ambiente simile a quello che un utente si attende quando effettua direttamente il login\&.
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.sp
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When
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\fB\-\fR
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is used, it must be specified before any
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\fBusername\fR\&. For portability it is recommended to use it as last option, before any
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\fBusername\fR\&. The other forms (\fB\-l\fR
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and
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\fB\-\-login\fR) do not have this restriction\&.
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.RE
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.PP
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\fB\-s\fR, \fB\-\-shell\fR\ \&\fISHELL\fR
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.RS 4
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La shell che verr\(`a invocata\&.
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.sp
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The invoked shell is chosen from (highest priority first):
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.PP
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.RS 4
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The shell specified with \-\-shell\&.
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.RE
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.PP
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.RS 4
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If
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\fB\-\-preserve\-environment\fR
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is used, the shell specified by the
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\fB$SHELL\fR
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environment variable\&.
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.RE
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.PP
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.RS 4
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The shell indicated in the
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/etc/passwd
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entry for the target user\&.
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.RE
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.PP
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.RS 4
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/bin/sh
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if a shell could not be found by any above method\&.
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.RE
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.sp
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If the target user has a restricted shell (i\&.e\&. the shell field of this user\*(Aqs entry in
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/etc/passwd
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is not listed in
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/etc/shells), then the
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\fB\-\-shell\fR
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option or the
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\fB$SHELL\fR
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environment variable won\*(Aqt be taken into account, unless
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\fBsu\fR
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is called by root\&.
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.RE
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.PP
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\fB\-m\fR, \fB\-p\fR, \fB\-\-preserve\-environment\fR
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.RS 4
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Preserve the current environment, except for:
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.PP
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\fB$PATH\fR
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.RS 4
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reset according to the
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/etc/login\&.defs
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options
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\fBENV_PATH\fR
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or
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\fBENV_SUPATH\fR
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(see below);
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.RE
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.PP
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\fB$IFS\fR
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.RS 4
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reset to
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\(Fo<space><tab><newline>\(Fc, if it was set\&.
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.RE
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.sp
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If the target user has a restricted shell, this option has no effect (unless
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\fBsu\fR
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is called by root)\&.
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.sp
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Note that the default behavior for the environment is the following:
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.PP
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.RS 4
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The
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\fB$HOME\fR,
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\fB$SHELL\fR,
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\fB$USER\fR,
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\fB$LOGNAME\fR,
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\fB$PATH\fR, and
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\fB$IFS\fR
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environment variables are reset\&.
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.RE
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.PP
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.RS 4
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If
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\fB\-\-login\fR
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is not used, the environment is copied, except for the variables above\&.
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.RE
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.PP
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.RS 4
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If
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\fB\-\-login\fR
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is used, the
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\fB$TERM\fR,
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\fB$COLORTERM\fR,
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\fB$DISPLAY\fR, and
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\fB$XAUTHORITY\fR
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environment variables are copied if they were set\&.
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.RE
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.PP
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.RS 4
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If
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\fB\-\-login\fR
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is used, the
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\fB$TZ\fR,
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\fB$HZ\fR, and
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\fB$MAIL\fR
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environment variables are set according to the
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/etc/login\&.defs
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options
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\fBENV_TZ\fR,
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\fBENV_HZ\fR,
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\fBMAIL_DIR\fR, and
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\fBMAIL_FILE\fR
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(see below)\&.
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.RE
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.PP
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.RS 4
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If
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\fB\-\-login\fR
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is used, other environment variables might be set by the
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\fBENVIRON_FILE\fR
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file (see below)\&.
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.RE
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.sp
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.RE
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.SH "AVVISI/CAVEAT"
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.PP
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This version of
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\fBsu\fR
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has many compilation options, only some of which may be in use at any particular site\&.
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.SH "CONFIGURAZIONE"
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.PP
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The following configuration variables in
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/etc/login\&.defs
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change the behavior of this tool:
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.PP
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\fBCONSOLE\fR (string)
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.RS 4
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Se definito, o il percorso completo di un file che contiene l\*(Aqelenco di nomi di device (uno per riga) oppure un elenco di nomi di device separati da \(Fo:\(Fc\&. L\*(Aqaccesso come root verr\(`a permesso solo attraverso questi device\&.
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.sp
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Se non definito, root potr\(`a accedere da qualsiasi device\&.
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.sp
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Il nome di device deve essere specificato senza il prefisso /dev\&.
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.RE
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.PP
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\fBCONSOLE_GROUPS\fR (string)
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.RS 4
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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\&.
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Use with caution \- it is possible for users to gain permanent access to these groups, even when not logged in on the console\&.
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.RE
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.PP
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\fBDEFAULT_HOME\fR (boolean)
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.RS 4
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Indica se permettere l\*(Aqaccesso al sistema anche se non si pu\(`o accedere alla directory home\&. Il valore predefinito \(`e no\&.
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.sp
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If set to
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\fIyes\fR, the user will login in the root (/) directory if it is not possible to cd to her home directory\&.
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.RE
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.PP
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\fBENV_HZ\fR (string)
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.RS 4
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If set, it will be used to define the HZ environment variable when a user login\&. The value must be preceded by
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\fIHZ=\fR\&. A common value on Linux is
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\fIHZ=100\fR\&.
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.RE
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.PP
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\fBENVIRON_FILE\fR (string)
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.RS 4
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Se questo file esiste ed \(`e leggibile, l\*(Aqambiente di login viene letto da l\(`i\&. Ogni riga deve essere nella forma nome=valore\&.
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.sp
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Le righe che iniziano con \(Fo#\(Fc sono trattate come commenti e ignorate\&.
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.RE
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.PP
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\fBENV_PATH\fR (string)
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.RS 4
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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
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\fI/bin:/usr/bin\fR) and can be preceded by
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\fIPATH=\fR\&. The default value is
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\fIPATH=/bin:/usr/bin\fR\&.
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.RE
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.PP
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\fBENV_SUPATH\fR (string)
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.RS 4
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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
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\fI/sbin:/bin:/usr/sbin:/usr/bin\fR) and can be preceded by
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\fIPATH=\fR\&. The default value is
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\fIPATH=/sbin:/bin:/usr/sbin:/usr/bin\fR\&.
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.RE
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.PP
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\fBENV_TZ\fR (string)
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.RS 4
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If set, it will be used to define the TZ environment variable when a user login\&. The value can be the name of a timezone preceded by
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\fITZ=\fR
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(for example
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\fITZ=CST6CDT\fR), or the full path to the file containing the timezone specification (for example
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/etc/tzname)\&.
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.sp
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If a full path is specified but the file does not exist or cannot be read, the default is to use
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\fITZ=CST6CDT\fR\&.
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.RE
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.PP
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\fBLOGIN_STRING\fR (string)
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.RS 4
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Il testo da utilizzare per richiedere la password\&. Il valore predefinito \(`e \(FoPassword: \(Fc o una sua traduzione\&. Se si imposta questa variabile allora il testo non verr\(`a tradotto\&.
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.sp
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If the string contains
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\fI%s\fR, this will be replaced by the user\*(Aqs name\&.
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.RE
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.PP
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\fBMAIL_CHECK_ENAB\fR (boolean)
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.RS 4
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Abilita la verifica e stampa a video dello stato della casella di posta al momento dell\*(Aqaccesso al sistema\&.
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.sp
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Andrebbe disabilitato se i file di avvio della shell effettuano gi\(`a questo controllo (\(Fomailx \-e\(Fc o equivalente)\&.
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.RE
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.PP
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\fBMAIL_DIR\fR (string)
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.RS 4
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La directory di spool per la posta\&. Questa \(`e necessaria per manipolare la casella di posta quando il corrispondente account utente viene modificato o cancellato\&. Se non \(`e specificata viene utilizzato un valore impostato al momento della compilazione\&.
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.RE
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.PP
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\fBMAIL_FILE\fR (string)
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.RS 4
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Imposta la posizione delle caselle di posta degli utenti relative alla loro directory home\&.
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.RE
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.PP
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The
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\fBMAIL_DIR\fR
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and
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\fBMAIL_FILE\fR
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variables are used by
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\fBuseradd\fR,
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\fBusermod\fR, and
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\fBuserdel\fR
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to create, move, or delete the user\*(Aqs mail spool\&.
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.PP
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If
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\fBMAIL_CHECK_ENAB\fR
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is set to
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\fIyes\fR, they are also used to define the
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\fBMAIL\fR
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environment variable\&.
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.PP
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\fBQUOTAS_ENAB\fR (boolean)
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.RS 4
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Enable setting of resource limits from
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/etc/limits
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and ulimit, umask, and niceness from the user\*(Aqs passwd gecos field\&.
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.RE
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.PP
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\fBSULOG_FILE\fR (string)
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.RS 4
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Se definito, tutta l\*(Aqattivit\(`a di \(Fosu\(Fc viene tracciata in questo file\&.
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.RE
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.PP
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\fBSU_NAME\fR (string)
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.RS 4
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Se definito \(`e il nome del comando da mostrare quando si esegue \(Fosu \-\(Fc\&. Ad esempio, se lo di definisce come \(Fosu\(Fc allora \(Fops\(Fc mostrer\(`a che il comando \(`e \(Fo\-su\(Fc\&. Se non definito, \(Fops\(Fc mostrer\(`a il nome della shell invocata, come \(Fo\-sh\(Fc\&.
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.RE
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.PP
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\fBSU_WHEEL_ONLY\fR (boolean)
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.RS 4
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If
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\fIyes\fR, the user must be listed as a member of the first gid 0 group in
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/etc/group
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(called
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\fIroot\fR
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on most Linux systems) to be able to
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\fBsu\fR
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to uid 0 accounts\&. If the group doesn\*(Aqt exist or is empty, no one will be able to
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\fBsu\fR
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to uid 0\&.
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.RE
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.PP
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\fBSYSLOG_SU_ENAB\fR (boolean)
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.RS 4
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Enable "syslog" logging of
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\fBsu\fR
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activity \- in addition to sulog file logging\&.
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.RE
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.PP
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\fBUSERGROUPS_ENAB\fR (boolean)
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.RS 4
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Abilita l\*(Aqimpostazione dei bit di gruppo di umask in modo che siano gli stessi dei bit del proprietario (esempio: 022 \-> 002, 077 \-> 007) per utenti non root a condizione che uid e gid siano identici e che il nome utente sia lo stesso del gruppo primario\&.
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.sp
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If set to
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\fIyes\fR,
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\fBuserdel\fR
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will remove the user\*(Aqs group if it contains no more members, and
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\fBuseradd\fR
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will create by default a group with the name of the user\&.
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.RE
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.SH "FILE"
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.PP
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/etc/passwd
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.RS 4
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Informazioni sugli account utente\&.
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.RE
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.PP
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/etc/shadow
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.RS 4
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Informazioni sicure sugli account utente\&.
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.RE
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.PP
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/etc/login\&.defs
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.RS 4
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Configurazione del pacchetto password shadow
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.RE
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.SH "VALORI RESTITUITI"
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.PP
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On success,
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\fBsu\fR
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returns the exit value of the command it executed\&.
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.PP
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If this command was terminated by a signal,
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\fBsu\fR
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returns the number of this signal plus 128\&.
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.PP
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If su has to kill the command (because it was asked to terminate, and the command did not terminate in time),
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\fBsu\fR
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returns 255\&.
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.PP
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Some exit values from
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\fBsu\fR
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are independent from the executed command:
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.PP
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\fI0\fR
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.RS 4
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success (\fB\-\-help\fR
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only)
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.RE
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.PP
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\fI1\fR
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.RS 4
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System or authentication failure
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.RE
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.PP
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\fI126\fR
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.RS 4
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The requested command was not found
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.RE
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.PP
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\fI127\fR
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.RS 4
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The requested command could not be executed
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.RE
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.SH "VEDERE ANCHE"
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.PP
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\fBlogin\fR(1),
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\fBlogin.defs\fR(5),
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\fBsg\fR(1),
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\fBsh\fR(1)\&.
|