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.\" Generator: DocBook XSL Stylesheets v1.73.2 <http://docbook.sf.net/>
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.\" Manual: User Commands
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.\" Source: User Commands
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.TH "PASSWD" "1" "03/04/2008" "User Commands" "User Commands"
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.TH "PASSWD" "1" "15/04/2009" "User Commands" "User Commands"
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command changes passwords for user accounts\. A normal user may only change the password for his/her own account, while the superuser may change the password for any account\.
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command changes passwords for user accounts\&. A normal user may only change the password for his/her own account, while the superuser may change the password for any account\&.
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also changes account information, such as the full name of the user, the user\'s login shell, or his/her password expiry date and interval\.
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also changes the account or associated password validity period\&.
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.SS "Modifiche delle password"
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The user is first prompted for his/her old password, if one is present\. This password is then encrypted and compared against the stored password\. The user has only one chance to enter the correct password\. The superuser is permitted to bypass this step so that forgotten passwords may be changed\.
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The user is first prompted for his/her old password, if one is present\&. This password is then encrypted and compared against the stored password\&. The user has only one chance to enter the correct password\&. The superuser is permitted to bypass this step so that forgotten passwords may be changed\&.
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After the password has been entered, password aging information is checked to see if the user is permitted to change the password at this time\. If not,
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After the password has been entered, password aging information is checked to see if the user is permitted to change the password at this time\&. If not,
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refuses to change the password and exits\.
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The user is then prompted twice for a replacement password\. The second entry is compared against the first and both are required to match in order for the password to be changed\.
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Then, the password is tested for complexity\. As a general guideline, passwords should consist of 6 to 8 characters including one or more characters from each of the following sets:
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refuses to change the password and exits\&.
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The user is then prompted twice for a replacement password\&. The second entry is compared against the first and both are required to match in order for the password to be changed\&.
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Then, the password is tested for complexity\&. As a general guideline, passwords should consist of 6 to 8 characters including one or more characters from each of the following sets:
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\h'-04'\(bu\h'+03'lettere minuscole
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\h'-04'\(bu\h'+03'segni di punteggiatura
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Care must be taken not to include the system default erase or kill characters\.
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Care must be taken not to include the system default erase or kill characters\&.
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will reject any password which is not suitably complex\.
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will reject any password which is not suitably complex\&.
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.SS "Suggerimenti per password utente"
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The security of a password depends upon the strength of the encryption algorithm and the size of the key space\. The
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The security of a password depends upon the strength of the encryption algorithm and the size of the key space\&. The
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System encryption method is based on the NBS DES algorithm and is very secure\. The size of the key space depends upon the randomness of the password which is selected\.
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Compromises in password security normally result from careless password selection or handling\. For this reason, you should not select a password which appears in a dictionary or which must be written down\. The password should also not be a proper name, your license number, birth date, or street address\. Any of these may be used as guesses to violate system security\.
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Your password must be easily remembered so that you will not be forced to write it on a piece of paper\. This can be accomplished by appending two small words together and separating each with a special character or digit\. For example, Pass%word\.
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Other methods of construction involve selecting an easily remembered phrase from literature and selecting the first or last letter from each word\. An example of this is:
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\h'-04'\(bu\h'+03'Non chiedere per chi suona la campana
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\h'-04'\(bu\h'+03'che produce
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\h'-04'\(bu\h'+03'NcXcslc
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You may be reasonably sure few crackers will have included this in their dictionaries\. You should, however, select your own methods for constructing passwords and not rely exclusively on the methods given here\.
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System encryption method is based on the NBS DES algorithm and is very secure\&. The size of the key space depends upon the randomness of the password which is selected\&.
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Compromises in password security normally result from careless password selection or handling\&. For this reason, you should not select a password which appears in a dictionary or which must be written down\&. The password should also not be a proper name, your license number, birth date, or street address\&. Any of these may be used as guesses to violate system security\&.
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You can find advices on how to choose a strong password on http://en\&.wikipedia\&.org/wiki/Password_strength
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This option can be used only with
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and causes show status for all users\.
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and causes show status for all users\&.
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\fB\-d\fR, \fB\-\-delete\fR
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Delete a user\'s password (make it empty)\. This is a quick way to disable a password for an account\. It will set the named account passwordless\.
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Delete a user\'s password (make it empty)\&. This is a quick way to disable a password for an account\&. It will set the named account passwordless\&.
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\fB\-e\fR, \fB\-\-expire\fR
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Immediately expire an account\'s password\. This in effect can force a user to change his/her password at the user\'s next login\.
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Immediately expire an account\'s password\&. This in effect can force a user to change his/her password at the user\'s next login\&.
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\fB\-h\fR, \fB\-\-help\fR
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Mostra un messaggio di aiuto ed esce\.
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Mostra un messaggio di aiuto ed esce\&.
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\fB\-i\fR, \fB\-\-inactive\fR \fIINACTIVE\fR
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This option is used to disable an account after the password has been expired for a number of days\. After a user account has had an expired password for
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This option is used to disable an account after the password has been expired for a number of days\&. After a user account has had an expired password for
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days, the user may no longer sign on to the account\.
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days, the user may no longer sign on to the account\&.
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\fB\-k\fR, \fB\-\-keep\-tokens\fR
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Indicate password change should be performed only for expired authentication tokens (passwords)\. The user wishes to keep their non\-expired tokens as before\.
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Indicate password change should be performed only for expired authentication tokens (passwords)\&. The user wishes to keep their non\-expired tokens as before\&.
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\fB\-l\fR, \fB\-\-lock\fR
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Lock the named account\. This option disables an account by changing the password to a value which matches no possible encrypted value, and by setting the account expiry field to 1\.
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Lock the password of the named account\&. This option disables a password by changing it to a value which matches no possible encrypted value (it adds a \(aa!\(aa at the beginning of the password)\&.
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Note that this does not disable the account\&. The user may still be able to login using another authentication token (e\&.g\&. an SSH key)\&. To disable the account, administrators should use
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\fBusermod \-\-expiredate 1\fR
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(this set the account\'s expire date to Jan 2, 1970)\&.
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Users with a locked password are not allowed to change their password\&.
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\fB\-m\fR, \fB\-\-mindays\fR \fIMIN_DAYS\fR
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Set the minimum number of days between password changes to
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\fIMIN_DAYS\fR\. A value of zero for this field indicates that the user may change his/her password at any time\.
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\fIMIN_DAYS\fR\&. A value of zero for this field indicates that the user may change his/her password at any time\&.
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\fB\-q\fR, \fB\-\-quiet\fR
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\fB\-r\fR, \fB\-\-repository\fR \fIREPOSITORY\fR
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\fB\-S\fR, \fB\-\-status\fR
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Display account status information\. The status information consists of 7 fields\. The first field is the user\'s login name\. The second field indicates if the user account is locked (L), has no password (NP), or has a usable password (P)\. The third field gives the date of the last password change\. The next four fields are the minimum age, maximum age, warning period, and inactivity period for the password\. These ages are expressed in days\.
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Display account status information\&. The status information consists of 7 fields\&. The first field is the user\'s login name\&. The second field indicates if the user account has a locked password (L), has no password (NP), or has a usable password (P)\&. The third field gives the date of the last password change\&. The next four fields are the minimum age, maximum age, warning period, and inactivity period for the password\&. These ages are expressed in days\&.
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\fB\-u\fR, \fB\-\-unlock\fR
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Unlock the named account\. This option re\-enables an account by changing the password back to its previous value (to value before using
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Unlock the password of the named account\&. This option re\-enables a password by changing the password back to its previous value (to the value before using the
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option), and by resetting the account expiry field\.
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option), and by resetting the account expiry field\&.
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\fB\-w\fR, \fB\-\-warndays\fR \fIWARN_DAYS\fR
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Set the number of days of warning before a password change is required\. The
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Set the number of days of warning before a password change is required\&. The
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option is the number of days prior to the password expiring that a user will be warned that his/her password is about to expire\.
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option is the number of days prior to the password expiring that a user will be warned that his/her password is about to expire\&.
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\fB\-x\fR, \fB\-\-maxdays\fR \fIMAX_DAYS\fR
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Set the maximum number of days a password remains valid\. After
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\fIMAX_DAYS\fR, the password is required to be changed\.
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Set the maximum number of days a password remains valid\&. After
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\fIMAX_DAYS\fR, the password is required to be changed\&.
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.SH "AVVISI/CAVEAT"
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Non tutte le opzioni potrebbero essere supportate\. Il controllo della complessità delle password varia da sistema a sistema\. L\e\'utente deve poter selezionare la possibilità di selezionare una password che ritenga sufficientemente complessa\. Gli utenti potrebbero non essere in condizione di modificare la propria password se NIS è abilitato e loro non hanno fatto il login sul server NIS\.
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Non tutte le opzioni potrebbero essere supportate\&. Il controllo della complessità delle password varia da sistema a sistema\&. L\e\'utente deve poter selezionare la possibilità di selezionare una password che ritenga sufficientemente complessa\&. Gli utenti potrebbero non essere in condizione di modificare la propria password se NIS è abilitato e loro non hanno fatto il login sul server NIS\&.
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.SH "CONFIGURATION"
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The following configuration variables in
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\fI/etc/login\.defs\fR
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\fI/etc/login\&.defs\fR
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change the behavior of this tool:
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\fBENCRYPT_METHOD\fR (string)
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This defines the system default encryption algorithm for encrypting passwords (if no algorithm are specified on the command line)\.
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This defines the system default encryption algorithm for encrypting passwords (if no algorithm are specified on the command line)\&.
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It can take one of these values:
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Note: this parameter overrides the
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\fBMD5_CRYPT_ENAB\fR
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Note: if you use PAM, it is recommended to set this variable consistently with the PAM modules configuration\.
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Note: if you use PAM, it is recommended to set this variable consistently with the PAM modules configuration\&.
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\fBMD5_CRYPT_ENAB\fR (boolean)
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Indicate if passwords must be encrypted using the MD5\-based algorithm\. If set to
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\fIyes\fR, new passwords will be encrypted using the MD5\-based algorithm compatible with the one used by recent releases of FreeBSD\. It supports passwords of unlimited length and longer salt strings\. Set to
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Indicate if passwords must be encrypted using the MD5\-based algorithm\&. If set to
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\fIyes\fR, new passwords will be encrypted using the MD5\-based algorithm compatible with the one used by recent releases of FreeBSD\&. It supports passwords of unlimited length and longer salt strings\&. Set to
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if you need to copy encrypted passwords to other systems which don\'t understand the new algorithm\. Default is
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if you need to copy encrypted passwords to other systems which don\'t understand the new algorithm\&. Default is
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This variable is superceded by the
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\fBENCRYPT_METHOD\fR
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variable or by any command line option used to configure the encryption algorithm\.
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This variable is deprecated\. You should use
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\fBENCRYPT_METHOD\fR\.
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Note: if you use PAM, it is recommended to set this variable consistently with the PAM modules configuration\.
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variable or by any command line option used to configure the encryption algorithm\&.
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This variable is deprecated\&. You should use
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\fBENCRYPT_METHOD\fR\&.
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Note: if you use PAM, it is recommended to set this variable consistently with the PAM modules configuration\&.
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\fBOBSCURE_CHECKS_ENAB\fR (boolean)
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Enable additional checks upon password changes\.
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Enable additional checks upon password changes\&.
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\fBPASS_ALWAYS_WARN\fR (boolean)
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Warn about weak passwords (but still allow them) if you are root\.
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Warn about weak passwords (but still allow them) if you are root\&.
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\fBPASS_CHANGE_TRIES\fR (number)
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Maximum number of attempts to change password if rejected (too easy)\.
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Maximum number of attempts to change password if rejected (too easy)\&.
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\fBPASS_MAX_LEN\fR (number), \fBPASS_MIN_LEN\fR (number)
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Number of significant characters in the password for crypt()\.
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Number of significant characters in the password for crypt()\&.
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\fBPASS_MAX_LEN\fR
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is 8 by default\. Don\'t change unless your crypt() is better\. This is ignored if
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is 8 by default\&. Don\'t change unless your crypt() is better\&. This is ignored if
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\fBMD5_CRYPT_ENAB\fR
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\fBSHA_CRYPT_MIN_ROUNDS\fR (number), \fBSHA_CRYPT_MAX_ROUNDS\fR (number)
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\fISHA512\fR, this defines the number of SHA rounds used by the encryption algorithm by default (when the number of rounds is not specified on the command line)\.
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With a lot of rounds, it is more difficult to brute forcing the password\. But note also that more CPU resources will be needed to authenticate users\.
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If not specified, the libc will choose the default number of rounds (5000)\.
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The values must be inside the 1000\-999999999 range\.
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\fISHA512\fR, this defines the number of SHA rounds used by the encryption algorithm by default (when the number of rounds is not specified on the command line)\&.
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With a lot of rounds, it is more difficult to brute forcing the password\&. But note also that more CPU resources will be needed to authenticate users\&.
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If not specified, the libc will choose the default number of rounds (5000)\&.
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The values must be inside the 1000\-999999999 range\&.
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If only one of the
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\fBSHA_CRYPT_MIN_ROUNDS\fR
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\fBSHA_CRYPT_MAX_ROUNDS\fR
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values is set, then this value will be used\.
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values is set, then this value will be used\&.
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\fBSHA_CRYPT_MIN_ROUNDS\fR
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\fBSHA_CRYPT_MAX_ROUNDS\fR, the highest value will be used\.
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\fBSHA_CRYPT_MAX_ROUNDS\fR, the highest value will be used\&.
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\fI/etc/passwd\fR
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informazioni sugli account utente\.
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informazioni sugli account utente\&.
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\fI/etc/shadow\fR
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Informazioni sicure sugli account di utenti\.
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Informazioni sicure sugli account di utenti\&.
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.SH "VALORI RESTITUITI"
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man/it/passwd.1
