As stated before /etc/shadows passwords are encrypted.
1) Username: It is used when user logs in. It should be between 1 and 32 characters in length.
2) Password: An x character indicates that encrypted password is stored in /etc/shadow file.
3) User ID (UID): Each user must be assigned a user ID (UID). UID 0 (zero) is reserved for root and UIDs 1-99 are reserved for other predefined accounts. Further UID 100-999 are reserved by system for administrative and system accounts/groups.
4) Group ID (GID): The primary group ID (stored in /etc/group file)
5) User ID Info: The comment field. It allow you to add extra information about the users such as user's full name, phone number etc. This field use by finger command.
6) Home directory: The absolute path to the directory the user will be in when they log in. If this directory does not exists then users directory becomes /
7) Command/shell: The absolute path of a command or shell (/bin/bash). Typically, this is a shell. Please note that it does not have to be a shell.
Your encrpted password is not stored in /etc/passwd file. It is stored in /etc/shadow file. In the good old days there was no great problem with this general read permission. Everybody could read the encrypted passwords, but the hardware was too slow to crack a well-chosen password, and moreover, the basic assumption used to be that of a friendly user-community.
Almost, all modern Linux / UNIX line operating systems use some sort of the shadow password suite, where /etc/passwd has asterisks (*) instead of encrypted passwords, and the encrypted passwords are in /etc/shadow which is readable by the superuser only.
02-02-2009
