path: root/man/sv/man1/passwd.1

'\" t
.\"     Title: passwd
.\"    Author: Julianne Frances Haugh
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 21-06-2024
.\"    Manual: User Commands
.\"    Source: shadow-utils 4.15.2
.\"  Language: Swedish
.\"
.TH "PASSWD" "1" "21-06-2024" "shadow\-utils 4\&.15\&.2" "User Commands"
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.SH "NAMN"
passwd \- \(:andra anv\(:andarl\(:osenord
.SH "SYNOPSIS"
.HP \w'\fBpasswd\fR\ 'u
\fBpasswd\fR [\fIoptions\fR] [\fILOGIN\fR]
.SH "BESKRIVNING"
.PP
The
\fBpasswd\fR
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\&.
\fBpasswd\fR
also changes the account or associated password validity period\&.
.SS "L\(:osenords\(:andringar"
.PP
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\&.
.PP
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,
\fBpasswd\fR
refuses to change the password and exits\&.
.PP
Anv\(:andaren fr\(oagas sedan tv\(oa g\(oanger efter ett ers\(:attande l\(:osenord\&. Den andra inmatningen j\(:amf\(:ors mot den f\(:orsta och b\(oada m\(oaste st\(:amma \(:overens f\(:or att l\(:osenordet ska \(:andras\&.
.PP
Then, the password is tested for complexity\&.
\fBpasswd\fR
will reject any password which is not suitably complex\&. Care must be taken not to include the system default erase or kill characters\&.
.SS "Tips f\(:or anv\(:andarl\(:osenord"
.PP
The security of a password depends upon the strength of the encryption algorithm and the size of the key space\&. The legacy
\fIUNIX\fR
System encryption method is based on the NBS DES algorithm\&. More recent methods are now recommended (see
\fBENCRYPT_METHOD\fR)\&. The size of the key space depends upon the randomness of the password which is selected\&.
.PP
Problem i l\(:osenordss\(:akerheten brukar normalt komma fr\(oan slarvigt valda l\(:osenord eller hantering\&. Av denna anledning b\(:or du inte v\(:alja ett l\(:osenord som finns i en ordbok eller som m\(oaste skrivas ner\&. L\(:osenordet b\(:or heller inte vara ett korrekt namn, ditt personnummer, f\(:odelsedatum eller gatuadress\&. Dessa kan anv\(:andas som gissningar f\(:or att ta sig in i systemet\&.
.PP
As a general guideline, passwords should be long and random\&. It\*(Aqs fine to use simple character sets, such as passwords consisting only of lowercase letters, if that helps memorizing longer passwords\&. For a password consisting only of lowercase English letters randomly chosen, and a length of 32, there are 26^32 (approximately 2^150) different possible combinations\&. Being an exponential equation, it\*(Aqs apparent that the exponent (the length) is more important than the base (the size of the character set)\&.
.PP
You can find advice on how to choose a strong password on http://en\&.wikipedia\&.org/wiki/Password_strength
.SH "FLAGGOR"
.PP
The options which apply to the
\fBpasswd\fR
command are:
.PP
\fB\-a\fR, \fB\-\-all\fR
.RS 4
This option can be used only with
\fB\-S\fR
and causes show status for all users\&.
.RE
.PP
\fB\-d\fR, \fB\-\-delete\fR
.RS 4
Ta bort en anv\(:andares l\(:osenord (g\(:or det blankt)\&. Detta \(:ar ett snabbt s\(:att att inaktivera ett l\(:osenord f\(:or ett konto\&. Det kommer att ta bort det angivna kontots l\(:osenord\&.
.RE
.PP
\fB\-e\fR, \fB\-\-expire\fR
.RS 4
L\(:osenordet f\(:or ett konto s\(:atts omedelbart som utg\(oanget\&. Detta kan tvinga en anv\(:andare att \(:andra sitt l\(:osenord vid n\(:asta inloggningsf\(:ors\(:ok\&.
.RE
.PP
\fB\-h\fR, \fB\-\-help\fR
.RS 4
Visa hj\(:alpmeddelande och avsluta\&.
.RE
.PP
\fB\-i\fR, \fB\-\-inactive\fR\ \&\fIINACTIVE\fR
.RS 4
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
\fIINACTIVE\fR
days, the user may no longer sign on to the account\&.
.RE
.PP
\fB\-k\fR, \fB\-\-keep\-tokens\fR
.RS 4
Indicate password change should be performed only for expired authentication tokens (passwords)\&. The user wishes to keep their non\-expired tokens as before\&.
.RE
.PP
\fB\-l\fR, \fB\-\-lock\fR
.RS 4
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)\&.
.sp
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
\fBusermod \-\-expiredate 1\fR
(this set the account\*(Aqs expire date to Jan 2, 1970)\&.
.sp
Users with a locked password are not allowed to change their password\&.
.RE
.PP
\fB\-n\fR, \fB\-\-mindays\fR\ \&\fIMIN_DAYS\fR
.RS 4
Set the minimum number of days between password changes to
\fIMIN_DAYS\fR\&. A value of zero for this field indicates that the user may change their password at any time\&.
.RE
.PP
\fB\-q\fR, \fB\-\-quiet\fR
.RS 4
Tyst l\(:age\&.
.RE
.PP
\fB\-r\fR, \fB\-\-repository\fR\ \&\fIREPOSITORY\fR
.RS 4
change password in
\fIREPOSITORY\fR
repository
.RE
.PP
\fB\-R\fR, \fB\-\-root\fR\ \&\fICHROOT_DIR\fR
.RS 4
Apply changes in the
\fICHROOT_DIR\fR
directory and use the configuration files from the
\fICHROOT_DIR\fR
directory\&. Only absolute paths are supported\&.
.RE
.PP
\fB\-P\fR, \fB\-\-prefix\fR\ \&\fIPREFIX_DIR\fR
.RS 4
Apply changes to configuration files under the root filesystem found under the directory
\fIPREFIX_DIR\fR\&. This option does not chroot and is intended for preparing a cross\-compilation target\&. Some limitations: NIS and LDAP users/groups are not verified\&. PAM authentication is using the host files\&. No SELINUX support\&.
.RE
.PP
\fB\-S\fR, \fB\-\-status\fR
.RS 4
Display account status information\&. The status information consists of 7 fields\&. The first field is the user\*(Aqs 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\&.
.RE
.PP
\fB\-u\fR, \fB\-\-unlock\fR
.RS 4
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
\fB\-l\fR
option)\&.
.RE
.PP
\fB\-w\fR, \fB\-\-warndays\fR\ \&\fIWARN_DAYS\fR
.RS 4
Set the number of days of warning before a password change is required\&. The
\fIWARN_DAYS\fR
option is the number of days prior to the password expiring that a user will be warned that their password is about to expire\&.
.RE
.PP
\fB\-x\fR, \fB\-\-maxdays\fR\ \&\fIMAX_DAYS\fR
.RS 4
Set the maximum number of days a password remains valid\&. After
\fIMAX_DAYS\fR, the password is required to be changed\&.
.sp
Passing the number
\fI\-1\fR
as
\fIMAX_DAYS\fR
will remove checking a password\*(Aqs validity\&.
.RE
.PP
\fB\-s\fR, \fB\-\-stdin\fR
.RS 4
This option is used to indicate that passwd should read the new password from standard input, which can be a pipe\&.
.RE
.SH "T\(:ANK P\(oA"
.PP
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\&.
.PP
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\&.
.SH "CONFIGURATION"
.PP
The following configuration variables in
/etc/login\&.defs
change the behavior of this tool:
.SH "FILER"
.PP
/etc/passwd
.RS 4
Anv\(:andarkontoinformation\&.
.RE
.PP
/etc/shadow
.RS 4
S\(:aker anv\(:andarkontoinformation\&.
.RE
.PP
/etc/login\&.defs
.RS 4
Shadow password suite configuration\&.
.RE
.SH "AVSLUTNINGSV\(:ARDEN"
.PP
The
\fBpasswd\fR
command exits with the following values:
.PP
\fI0\fR
.RS 4
success
.RE
.PP
\fI1\fR
.RS 4
permission denied
.RE
.PP
\fI2\fR
.RS 4
invalid combination of options
.RE
.PP
\fI3\fR
.RS 4
unexpected failure, nothing done
.RE
.PP
\fI4\fR
.RS 4
unexpected failure,
passwd
file missing
.RE
.PP
\fI5\fR
.RS 4
passwd
file busy, try again
.RE
.PP
\fI6\fR
.RS 4
invalid argument to option
.RE
.SH "SE OCKS\(oA"
.PP
\fBchpasswd\fR(8),
\fBmakepasswd\fR(1),
\fBpasswd\fR(5),
\fBshadow\fR(5),
\fBlogin.defs\fR(5),
\fBusermod\fR(8)\&.
.PP
The following web page comically (yet correctly) compares the strength of two different methods for choosing a password: "https://xkcd\&.com/936/"