>>9615
/etc/passwd is the name of a file that contains all the system passwords
/bin/passwd is the name of the program that you use to set/change passwords for users on the system. Settings files live in /etc, and programs live in /bin directory (there's a lot more to it, but that's a very basic idea)
sudo is the command used to run something as root user when you are logged in as a different user.
It sounds like you have a typo in your book, and it should either be something like
cat /etc/passwd
to view the password file entries.*
sudo passwd some-user-name
to set/change the password for some-user-name
try
man passwd
to see how the command works.
*(passwords are not stored, only the hash of the password - which is a one-way mathematical operation on the password that results in a unique text called the "hash". You can't take a hash and reverse it into a password - which is why people pre-calculate common passwords and store hash databases for password matching/hacking)