PASSWD(5) File Formats Manual PASSWD(5)
passwd - password file
Passwd contains for each user the following information:
name (login name, contains no upper case)
numerical user ID
numerical group ID
user's real name, office, extension, home phone.
initial working directory
program to use as Shell
The name may contain `&', meaning insert the login name. This informa-
tion is set by the chfn(1) command and used by the finger(1) command.
This is an ASCII file. Each field within each user's entry is sepa-
rated from the next by a colon. Each user is separated from the next
by a new-line. If the password field is null, no password is demanded;
if the Shell field is null, then /bin/sh is used.
This file resides in directory /etc. Because of the encrypted pass-
words, it can and does have general read permission and can be used,
for example, to map numerical user ID's to names.
Appropriate precautions must be taken to lock the file against changes
if it is to be edited with a text editor; vipw(8) does the necessary
getpwent(3), login(1), crypt(3), passwd(1), group(5), chfn(1), fin-
ger(1), vipw(8), adduser(8)
A binary indexed file format should be available for fast access.
User information (name, office, etc.) should be stored elsewhere.
15 January 1983 PASSWD(5)