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1.TH PASSWD 1
2.SH NAME
3passwd \- change login password
4.SH SYNOPSIS
5.B passwd
6[ name ]
7.SH DESCRIPTION
8This command changes (or installs) a password
9associated with the user
10.IR name
11(your own name by default).
12.PP
13The program prompts for the old password and then for the new one.
14The caller must supply both.
15The new password must be typed twice, to forestall mistakes.
16.PP
17New passwords must be at least four characters long if they use
18a sufficiently rich alphabet and at least six characters long
19if monocase.
20These rules are relaxed if you are insistent enough.
21.PP
22Only the owner of the name or the super-user may change a password;
23the owner must prove he knows the old password.
24.SH FILES
25/etc/passwd
26.SH "SEE ALSO"
27login(1), passwd(5), crypt(3)
28.br
29Robert Morris and Ken Thompson,
30.I Password Security: A Case History