man-pages/shadow.5

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.\"$Id: shadow.5,v 1.13 2005/03/24 06:24:36 kloczek Exp $
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.TH SHADOW 5
.SH NAME
shadow \- encrypted password file
.SH DESCRIPTION
\fIshadow\fR contains the encrypted password information for user's accounts
and optional the password aging information. Included is
.IP "" .5i
Login name
.IP "" .5i
Encrypted password
.IP "" .5i
Days since Jan 1, 1970 that password was last changed
.IP "" .5i
Days before password may be changed
.IP "" .5i
Days after which password must be changed
.IP "" .5i
Days before password is to expire that user is warned
.IP "" .5i
Days after password expires that account is disabled
.IP "" .5i
Days since Jan 1, 1970 that account is disabled
.IP "" .5i
A reserved field
.PP
The password field must be filled. The encryped password consists of 13 to
24 characters from the 64 characters alphabet a thru z, A thru Z, 0 thru 9,
\&\. and /. Optionally it can start with a "$" character. This means the
encrypted password was generated using another (not DES) algorithm. For
example if it starts with "$1$" it means the MD5-based algorithm was used.
.PP
Refer to \fBcrypt\fR(3) for details on how this string is interpreted.
.PP
The date of the last password change is given as the number of days since
Jan 1, 1970. The password may not be changed again until the proper number
of days have passed, and must be changed after the maximum number of days.
If the minimum number of days required is greater than the maximum number of
day allowed, this password may not be changed by the user.
.PP
An account is considered to be inactive and is disabled if the password is
not changed within the specified number of days after the password expires.
An account will also be disabled on the specified day regardless of other
password expiration information.
.PP
This information supercedes any password or password age information present
in \fI/etc/passwd\fR.
.PP
This file must not be readable by regular users if password security is to
be maintained.
.SH FILES
\fI/etc/passwd\fR \ - user account information
.br
\fI/etc/shadow\fR \ - encrypted user passwords
.SH SEE ALSO
.BR chage (1),
.BR login (1),
.BR passwd (1),
.BR su (1),
.BR passwd (5),
.BR pwconv (8),
.BR pwunconv (8),
.BR sulogin (8)
.SH AUTHOR
Julianne Frances Haugh (jockgrrl@ix.netcom.com)