Passwd file

[Jyrki Kuoppala]

>What is the purpose of the following /etc/passwd entry?
>
>::0:0:::    (null login, password, and shell)

It's a safeguard against bad memory; it lets you get superuser even if
you someday will forget the root password.  It's also useful if you go
for a vacation and there's somebody else administering the machine; if
you use this feature you don't have to tell the root password to that
somebody, he won't need it.

A variation:

+::0:0::: 

This is not as good, because it works only on some systems and even
then it doesn't work if the yellow pages is running.

If you want to use this feature and don't want to type all those
colons in (you'll easily type a wrong count of them) just say

echo '' >> /etc/passwd

and change somebody's login password.

Enjoy,

//Jyrki