Понедельник (09/07/09)

/dev/ttyp5
09:53:31
$whatis intro
PASSWD(1)                        User Commands                       PASSWD(1)
intro (7)            - Introduction to overview, conventions, and miscellany section
       passwd - change user password
intro (4)            - Introduction to special files
SYNOPSIS
intro (1)            - Introduction to user commands
intro (8)            - Introduction to administration and privileged commands
       passwd changes passwords for user accounts. A normal user may only
intro (2)            - Introduction to system calls while the super user may
       change the password for any account.  passwd also changes account
intro (6)            - Introduction to games the user, the user's login shell,
       or his/her password expiry date and interval.
intro (5)            - Introduction to file formats
   Password Changes
intro (3)            - Introduction to library functionsrd, 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 super user is permitted to bypass this step so that forgotten
       passwords may be changed.
       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, passwd refuses to change the password and exits.
       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
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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:
       o  lower case alphabetics
       o  digits 0 thru 9
       o  punctuation marks
       Care must be taken not to include the system default erase or kill
       characters.  passwd will reject any password which is not suitably
       complex.
   Hints for user passwords
       The security of a password depends upon the strength of the encryption
       algorithm and the size of the key space. The UNIX 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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       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.
       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.
       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:
       o  Ask not for whom the bell tolls
       o  which produces
       o  An4wtbt
       You may be reasonably sure few crackers will have included this in
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       constructing passwords and not rely exclusively on the methods given
       here.
OPTIONS
       The options which apply to the passwd command are:
       -a, --all
          This option can be used only with -S and causes show status for all
          users.
       -d, --delete
          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.
       -e, --expire
          Immediately expire an account's password. This in effect can force a
          user to change his/her password at the user's next login.
       -h, --help
          Display help message and exit.
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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 INACTIVE days, the user may no longer sign on
          to the account.
       -k, --keep-tokens
          Indicate password change should be performed only for expired
          authentication tokens (passwords). The user wishes to keep their
          non-expired tokens as before.
       -l, --lock
          Lock the named account. This option disables an account by changing
          the password to a value which matches no possible encrypted value.
       -m, --mindays MIN_DAYS
          Set the minimum number of days between password changes to MIN_DAYS.
          A value of zero for this field indicates that the user may change
          his/her password at any time.
       -q, --quiet
          Quiet mode.
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          change password in REPOSITORY repository
       -S, --status
          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.
       -u, --unlock
          Unlock the named account. This option re-enables an account by
          changing the password back to its previous value (to value before
          using -l option).
       -w, --warndays WARN_DAYS
          Set the number of days of warning before a password change is
          required. The WARN_DAYS 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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          Set the maximum number of days a password remains valid. After
          MAX_DAYS, the password is required to be changed.
CAVEATS
       Not all options may be supported. Password complexity checking may vary
       from site to site. The user is urged to select a password as complex as
       he or she feels comfortable with. Users may not be able to change their
       password on a system if NIS is enabled and they are not logged into the
       NIS server.
FILES
       /etc/passwd
          User account information.
       /etc/shadow
          Secure user account information.
EXIT VALUES
       The passwd command exits with the following values:
       0
          success
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          required. The WARN_DAYS 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.
       -x, --maxdays MAX_DAYS
          Set the maximum number of days a password remains valid. After
          MAX_DAYS, the password is required to be changed.
CAVEATS
       Not all options may be supported. Password complexity checking may vary
       from site to site. The user is urged to select a password as complex as
       he or she feels comfortable with. Users may not be able to change their
       password on a system if NIS is enabled and they are not logged into the
       NIS server.
FILES
       /etc/passwd
          User account information.
       /etc/shadow
          Secure user account information.
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       o  An4wtbt
       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.
OPTIONS
       The options which apply to the passwd command are:
       -a, --all
          This option can be used only with -S and causes show status for all
          users.
       -d, --delete
          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.
       -e, --expire
          Immediately expire an account's password. This in effect can force a
 ESC[5~
       The passwd command exits with the following values:days prior to the
          password expiring that a user will be warned that his/her password
       0  is about to expire.e and exit.
          success
       -x, --maxdays MAX_DAYSITORY
       1  Set the maximum number of days a password remains valid. Afteras
          permission deniedsword is required to be changed.ccount has had an
       -S, --statusassword for INACTIVE days, the user may no longer sign on
       2  Display account status information. The status information consists
          invalid combination of options Password complexity checking may vary
       from site to site. The user is urged to select a password as complex as
 ESC[5~
       3e or she feels comfortable with. Users may not be able to change their
       method is based on the NBS DES algorithm and is very secure. The size
          unexpected failure, nothing doneled and they are not logged into the
       -h, --help space depends upon the randomness of the password which is
       NIS server.imum age, warning period, and inactivity period for the
          Display help message and exit.or a replacement password. The second
       4  password. These ages are expressed in days.
       You may be reasonably sure few crackers will have included this in in
          unexpected failure, passwd file missing
       -i, --inactive INACTIVE should, however, select your own methods forord
       /etc/passwdknamed account. This option disables an account by changing
          This option is used to disable an account after the password hasn
       5  User account information. This option re-enables an account bylue.
          been expired for a number of days. After a user account has had an
          passwd file busy, try againto its previous value (to value before
          expired password for INACTIVE days, the user may no longer sign on
       /etc/shadow option).YS
          to the account.eet address. Any of these may be used as guesses to
       6  Secure user account information.etween password changes to MIN_DAYS.
       The options which apply to the passwd command are: the super user may
          invalid argument to optionield indicates that the user may change
       -k, --keep-tokenshabeticsny account.  passwd also changes account
          Indicate password change should be performed only for expiredforced,
          authentication tokens (passwords). The user wishes to keep theirall
          non-expired tokens as before.arating each with a special character
       or digit. For example, Pass%word.
       -l, --locktefirst prompted for his/her old password, if one is present.
          Lock the named account. This option disables an account by changing
          the password to a value which matches no possible encrypted value.ch
          passwordless. of this is:to bypass this step so that forgotten
       -m, --mindays MIN_DAYSed.
          Set the minimum number of days between password changes to MIN_DAYS.
          A value of zero for this field indicates that the user may changee a