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PASSWD(1)                        User Commands                       PASSWD(1)

NAME
       passwd - change user password

SYNOPSIS
       passwd [options] [LOGIN]

DESCRIPTION
       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.

   Password Changes
       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.

       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.

       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 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.

       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.

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

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 their password at the user's next login.

       -h, --help
           Display help message and exit.

       -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
           Quiet mode.

       -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.

CAVEATS
       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.

FILES
       /etc/passwd
           User account information.

       /etc/shadow
           Secure user account information.

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

EXIT VALUES
       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

SEE ALSO
       chpasswd(8), passwd(5), shadow(5), usermod(8).

shadow-utils 4.8.1                02/06/2024                         PASSWD(1)
OPENSSL-CMDS(1SSL)                  OpenSSL                 OPENSSL-CMDS(1SSL)

NAME
       asn1parse, ca, ciphers, cms, crl, crl2pkcs7, dgst, dhparam, dsa,
       dsaparam, ec, ecparam, enc, engine, errstr, gendsa, genpkey, genrsa,
       info, kdf, mac, nseq, ocsp, passwd, pkcs12, pkcs7, pkcs8, pkey,
       pkeyparam, pkeyutl, prime, rand, rehash, req, rsa, rsautl, s_client,
       s_server, s_time, sess_id, smime, speed, spkac, srp, storeutl, ts,
       verify, version, x509 - OpenSSL application commands

SYNOPSIS
       openssl cmd -help | [-option | -option arg] ... [arg] ...

DESCRIPTION
       Every cmd listed above is a (sub-)command of the openssl(1)
       application.  It has its own detailed manual page at openssl-cmd(1).
       For example, to view the manual page for the openssl dgst command, type
       "man openssl-dgst".

OPTIONS
       Among others, every subcommand has a help option.

       -help
           Print out a usage message for the subcommand.

SEE ALSO
       openssl(1), openssl-asn1parse(1), openssl-ca(1), openssl-ciphers(1),
       openssl-cms(1), openssl-crl(1), openssl-crl2pkcs7(1), openssl-dgst(1),
       openssl-dhparam(1), openssl-dsa(1), openssl-dsaparam(1), openssl-ec(1),
       openssl-ecparam(1), openssl-enc(1), openssl-engine(1),
       openssl-errstr(1), openssl-gendsa(1), openssl-genpkey(1),
       openssl-genrsa(1), openssl-info(1), openssl-kdf(1), openssl-mac(1),
       openssl-nseq(1), openssl-ocsp(1), openssl-passwd(1), openssl-pkcs12(1),
       openssl-pkcs7(1), openssl-pkcs8(1), openssl-pkey(1),
       openssl-pkeyparam(1), openssl-pkeyutl(1), openssl-prime(1),
       openssl-rand(1), openssl-rehash(1), openssl-req(1), openssl-rsa(1),
       openssl-rsautl(1), openssl-s_client(1), openssl-s_server(1),
       openssl-s_time(1), openssl-sess_id(1), openssl-smime(1),
       openssl-speed(1), openssl-spkac(1), openssl-srp(1),
       openssl-storeutl(1), openssl-ts(1), openssl-verify(1),
       openssl-version(1), openssl-x509(1),

HISTORY
       Initially, the manual page entry for the "openssl cmd" command used to
       be available at cmd(1). Later, the alias openssl-cmd(1) was introduced,
       which made it easier to group the openssl commands using the apropos(1)
       command or the shell's tab completion.

       In order to reduce cluttering of the global manual page namespace, the
       manual page entries without the 'openssl-' prefix have been deprecated
       in OpenSSL 3.0 and will be removed in OpenSSL 4.0.

COPYRIGHT
       Copyright 2019-2020 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use
       this file except in compliance with the License.  You can obtain a copy
       in the file LICENSE in the source distribution or at
       <https://www.openssl.org/source/license.html>.

3.0.2                             2026-04-07                OPENSSL-CMDS(1SSL)
PASSWD(5)                File Formats and Conversions                PASSWD(5)

NAME
       passwd - the password file

DESCRIPTION
       /etc/passwd contains one line for each user account, with seven fields
       delimited by colons (":"). These fields are:

       o   login name

       o   optional encrypted password

       o   numerical user ID

       o   numerical group ID

       o   user name or comment field

       o   user home directory

       o   optional user command interpreter

       If the password field is a lower-case "x", then the encrypted password
       is actually stored in the shadow(5) file instead; there must be a
       corresponding line in the /etc/shadow file, or else the user account is
       invalid.

       The encrypted password field may be empty, in which case no password is
       required to authenticate as the specified login name. However, some
       applications which read the /etc/passwd file may decide not to permit
       any access at all if the password field is blank.

       A password field which starts with an exclamation mark means that the
       password is locked. The remaining characters on the line represent the
       password field before the password was locked.

       Refer to crypt(3) for details on how this string is interpreted.

       If the password field contains some string that is not a valid result
       of crypt(3), for instance ! or *, the user will not be able to use a
       unix password to log in (but the user may log in the system by other
       means).

       The comment field is used by various system utilities, such as
       finger(1).

       The home directory field provides the name of the initial working
       directory. The login program uses this information to set the value of
       the $HOME environmental variable.

       The command interpreter field provides the name of the user's command
       language interpreter, or the name of the initial program to execute.
       The login program uses this information to set the value of the $SHELL
       environmental variable. If this field is empty, it defaults to the
       value /bin/sh.

FILES
       /etc/passwd
           User account information.

       /etc/shadow
           optional encrypted password file

       /etc/passwd-
           Backup file for /etc/passwd.

           Note that this file is used by the tools of the shadow toolsuite,
           but not by all user and password management tools.

SEE ALSO
       crypt(3), getent(1), getpwnam(3), login(1), passwd(1), pwck(8),
       pwconv(8), pwunconv(8), shadow(5), su(1), sulogin(8).

shadow-utils 4.8.1                02/06/2024                         PASSWD(5)