PASSWD(5) File Formats and Conversions PASSWD(5)
passwd - the password file
/etc/passwd contains one line for each user account, with seven fields
delimited by colons (":"). These fields are:
o login name
o optional encrypted password
o numerical user ID
o numerical group ID
o user name or comment field
o user home directory
o optional user command interpreter
The encrypted password field may be blank, in which case no password is
required to authenticate as the specified login name. However, some
applications which read the /etc/passwd file may decide not to permit
any access at all if the password field is blank. If the password field
is a lower-case "x", then the encrypted password is actually stored in
the shadow(5) file instead; there must be a corresponding line in the
/etc/shadow file, or else the user account is invalid. If the password
field is any other string, then it will be treated as an encrypted
password, as specified by crypt(3).
The comment field is used by various system utilities, such as
The home directory field provides the name of the initial working
directory. The login program uses this information to set the value of
the $HOME environmental variable.
The command interpreter field provides the name of the user's command
language interpreter, or the name of the initial program to execute.
The login program uses this information to set the value of the $SHELL
environmental variable. If this field is empty, it defaults to the
User account information.
optional encrypted password file
getent(1), login(1), passwd(1), su(1), crypt(3), getpwnam(3),
shadow(5), pwconv(8), pwunconv(8), sulogin(8).
File Formats and Conversions 11/14/2009 PASSWD(5)