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 4.8.1                                 06-02-2024                                          PASSWD(1)