'\" t
.\"     Title: chpasswd
.\"    Author: Julianne Frances Haugh
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 01/04/2024
.\"    Manual: System Management Commands
.\"    Source: shadow-utils 4.15.1
.\"  Language: Italian
.\"
.TH "CHPASSWD" "8" "01/04/2024" "shadow\-utils 4\&.15\&.1" "System Management Commands"
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.SH "NOME"
chpasswd \- aggiorna le password in modo non interattivo
.SH "SINOSSI"
.HP \w'\fBchpasswd\fR\ 'u
\fBchpasswd\fR [\fIoptions\fR]
.SH "DESCRIZIONE"
.PP
The
\fBchpasswd\fR
command reads a list of user name and password pairs from standard input and uses this information to update a group of existing users\&. Each line is of the format:
.PP
\fIuser_name\fR:\fIpassword\fR
.PP
By default the passwords must be supplied in clear\-text, and are encrypted by
\fBchpasswd\fR\&. Also the password age will be updated, if present\&.
.PP
By default, passwords are encrypted by PAM, but (even if not recommended) you can select a different encryption method with the
\fB\-e\fR,
\fB\-m\fR, or
\fB\-c\fR
options\&.
.PP
Except when PAM is used to encrypt the passwords,
\fBchpasswd\fR
first updates all the passwords in memory, and then commits all the changes to disk if no errors occurred for any user\&.
.PP
When PAM is used to encrypt the passwords (and update the passwords in the system database) then if a password cannot be updated
\fBchpasswd\fR
continues updating the passwords of the next users, and will return an error code on exit\&.
.PP
Questo comando \(`e appositamente pensato per grossi sistemi in cui si abbia la necessit\(`a di creare molti account nello stesso momento\&.
.SH "OPZIONI"
.PP
The options which apply to the
\fBchpasswd\fR
command are:
.PP
\fB\-c\fR, \fB\-\-crypt\-method\fR\ \&\fIMETHOD\fR
.RS 4
Utilizza il metodo specificato per cifrare le password\&.
.sp
The available methods are
\fIDES\fR,
\fIMD5\fR, \fISHA256\fR, \fISHA512\fR, \fIYESCRYPT\fR
and
\fINONE\fR
if your libc supports these methods\&.
.sp
PAM viene utilizzato, in maniera predefinita, per cifrare le password\&.
.RE
.PP
\fB\-e\fR, \fB\-\-encrypted\fR
.RS 4
Le password fornite sono in forma cifrata\&.
.RE
.PP
\fB\-h\fR, \fB\-\-help\fR
.RS 4
Mostra un messaggio di aiuto ed esce\&.
.RE
.PP
\fB\-m\fR, \fB\-\-md5\fR
.RS 4
Usa la cifratura MD5 anzich\('e DES quando le password fornite non sono cifrate\&.
.RE
.PP
\fB\-R\fR, \fB\-\-root\fR\ \&\fICHROOT_DIR\fR
.RS 4
Apply changes in the
\fICHROOT_DIR\fR
directory and use the configuration files from the
\fICHROOT_DIR\fR
directory\&. Only absolute paths are supported\&.
.RE
.PP
\fB\-P\fR, \fB\-\-prefix\fR\ \&\fIPREFIX_DIR\fR
.RS 4
Apply changes to configuration files under the root filesystem found under the directory
\fIPREFIX_DIR\fR\&. This option does not chroot and is intended for preparing a cross\-compilation target\&. Some limitations: NIS and LDAP users/groups are not verified\&. PAM authentication is using the host files\&. No SELINUX support\&.
.RE
.PP
\fB\-s\fR, \fB\-\-sha\-rounds\fR\ \&\fIROUNDS\fR
.RS 4
Usa il numero specificato di cicli per cifrare la password\&.
.sp
You can only use this option with crypt method:
\fISHA256\fR \fISHA512\fR
\fIYESCRYPT\fR
.sp
By default, the number of rounds for SHA256 or SHA512 is defined by the SHA_CRYPT_MIN_ROUNDS and SHA_CRYPT_MAX_ROUNDS variables in
/etc/login\&.defs\&.
.sp
A minimal value of 1000 and a maximal value of 999,999,999 will be enforced for SHA256 and SHA512\&. The default number of rounds is 5000\&.
.sp
By default, the number of rounds for YESCRYPT is defined by the YESCRYPT_COST_FACTOR in
/etc/login\&.defs\&.
.sp
A minimal value of 1 and a maximal value of 11 will be enforced for YESCRYPT\&. The default number of rounds is 5\&.
.RE
.SH "AVVISI/CAVEAT"
.PP
Ricordarsi di impostare i permessi o umask in modo da prevenire la lettura in chiaro da parte di altri utenti\&.
.SH "CONFIGURAZIONE"
.PP
The following configuration variables in
/etc/login\&.defs
change the behavior of this tool:
.SH "FILE"
.PP
/etc/passwd
.RS 4
Informazioni sugli account utente\&.
.RE
.PP
/etc/shadow
.RS 4
Informazioni sicure sugli account utente\&.
.RE
.PP
/etc/login\&.defs
.RS 4
Configurazione del pacchetto password shadow
.RE
.PP
/etc/pam\&.d/chpasswd
.RS 4
PAM configuration for
\fBchpasswd\fR\&.
.RE
.SH "VEDERE ANCHE"
.PP
\fBpasswd\fR(1),
\fBnewusers\fR(8),
\fBlogin.defs\fR(5),
\fBuseradd\fR(8)\&.