passwd

PASSWD(1)                      Användarkommandon                     PASSWD(1)



NAMN
       passwd - ändra användarlösenord

SYNOPSIS
       passwd [flaggor] [INLOGGNINGSNAMN]

BESKRIVNING
       The passwd command changes passwords for user accounts. A normal user
       may only change the password for their own account, while the superuser
       may change the password for any account.  passwd also changes the
       account or associated password validity period.

   Lösenordsändringar
       The user is first prompted for their 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.

       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.

       Användaren frågas sedan två gånger efter ett ersättande lösenord. Den
       andra inmatningen jämförs mot den första och båda måste stämma överens
       för att lösenordet ska ändras.

       Sedan testas lösenordet för sin komplexitet. Som en allmän riktlinje
       bör lösenord innehålla 6 till 8 tecken och inkluderas ett eller flera
       tecken från var och en av följande punkter:

       ·   gemena bokstäver ur alfabetet

       ·   siffrorna 0 till 9

       ·   skiljetecken

       Care must be taken not to include the system default erase or kill
       characters.  passwd will reject any password which is not suitably
       complex.

   Tips för användarlösenord
       The security of a password depends upon the strength of the encryption
       algorithm and the size of the key space. The legacy UNIX System
       encryption method is based on the NBS DES algorithm. More recent
       methods are now recommended (see ENCRYPT_METHOD). The size of the key
       space depends upon the randomness of the password which is selected.

       Problem i lösenordssäkerheten brukar normalt komma från slarvigt valda
       lösenord eller hantering. Av denna anledning bör du inte välja ett
       lösenord som finns i en ordbok eller som måste skrivas ner. Lösenordet
       bör heller inte vara ett korrekt namn, ditt personnummer, födelsedatum
       eller gatuadress. Dessa kan användas som gissningar för att ta sig in i
       systemet.

       You can find advice on how to choose a strong password on
       http://en.wikipedia.org/wiki/Password_strength

FLAGGOR
       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
           Ta bort en användares lösenord (gör det blankt). Detta är ett
           snabbt sätt att inaktivera ett lösenord för ett konto. Det kommer
           att ta bort det angivna kontots lösenord.

       -e, --expire
           Lösenordet för ett konto sätts omedelbart som utgånget. Detta kan
           tvinga en användare att ändra sitt lösenord vid nästa
           inloggningsförsök.

       -h, --help
           Visa hjälpmeddelande och avsluta.

       -i, --inactive INACTIVE
           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 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 ´!´ at the beginning of the password).

           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 usermod
           --expiredate 1 (this set the account's expire date to Jan 2, 1970).

           Users with a locked password are not allowed to change their
           password.

       -n, --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 their password at any time.

       -q, --quiet
           Tyst läge.

       -r, --repository REPOSITORY
           change password in REPOSITORY repository

       -R, --root CHROOT_DIR
           Apply changes in the CHROOT_DIR directory and use the configuration
           files from the CHROOT_DIR directory.

       -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 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.

       -u, --unlock
           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 -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 their 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.

           Passing the number -1 as MAX_DAYS will remove checking a password's
           validity.

TÄNK PÅ
       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.

       passwd uses PAM to authenticate users and to change their passwords.

FILER
       /etc/passwd
           Användarkontoinformation.

       /etc/shadow
           Säker användarkontoinformation.

       /etc/pam.d/passwd
           PAM configuration for passwd.

AVSLUTNINGSVÄRDEN
       The passwd command exits with the following values:

       0
           success

       1
           permission denied

       2
           invalid combination of options

       3
           unexpected failure, nothing done

       4
           unexpected failure, passwd file missing

       5
           passwd file busy, try again

       6
           invalid argument to option

SE OCKSÅ
       chpasswd(8), passwd(5), shadow(5), usermod(8).



shadow-utils 4.8                  15-12-2019                         PASSWD(1)