passwd - Password files
A passwd file is a file consisting of records separated by
newline characters, one record per user, containing seven
colon (:) separated fields. These fields are as follows:
User's login name. The default length is 8 characters.
User's encrypted password. User's ID User's login group
ID General information about the user User's home directory
User's login shell
The name field is the login used to access the computer
account, and the uid field is the number associated with
it. They should both be unique across the system (and
often across a group of systems) since they control file
While it is possible to have multiple entries with identical
login names and/or identical user gid's, it is usually
a mistake to do so. Routines that manipulate these files
will often return only one of the multiple entries, and
that one by random selection.
The login name must never begin with a hyphen (-); also,
it is strongly suggested that neither uppercase characters
or dots (.) be part of the name, as this tends to confuse
mailers. No field may contain a colon (:) as this has
been used historically to separate the fields in the user
The password field is the encrypted form of the password.
If the password field is empty, no password is required to
gain access to the machine. Because these files contain
the encrypted user passwords, they should not be readable
by anyone without appropriate privileges.
Use the vipw command to edit password entries. This
ensures that the hashed password database is rebuilt.
If you have enhanced security installed on your system,
the password field contains an asterisk (*). The encrypted
password is stored in the user's protected password
The gid field is the group that the user will be placed in
upon login. Since the operating system supports multiple
groups (see the groups command) this field currently has
little special meaning.
The gecos field normally contains comma (,) separated subfields
User's full name User's office number User's work phone
number User's home phone number
This information is used by the finger command.
The user's home directory is the full UNIX pathname where
the user will be placed on login.
The shell field is the command interpreter the user
prefers. If the shell field is empty, the Bourne shell
(/bin/sh) is assumed.
The allowable values for the UID are unsigned numbers from
0 to 65535.
The command pwck can be used to verify the accuracy of
data entered in the passwd file.
PRIVILEGED Account,,,:/etc/operator: guest:Nologin:-2:-2:anonymous
Commands: login(1), passwd(1), pwck(8), vipw(8)
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