The user's password information is located in a file named /etc/passwd. This is an ASCII file and is readable by everyone, which isn't a problem because all the security information is located elsewhere (as we will see later). For the moment, we'll ignore the default entries that are in the file—suffice it to say that they are required by the system and their use will be explained as we come across them.
Let's have a look at what the password file contains:
hydrogen# cat /etc/passwd root:x:0:1:Super-User:/:/sbin/sh daemon:x:1:1::/: bin:x:2:2::/usr/bin: sys:x:3:3::/:/bin/ksh adm:x:4:4:Admin:/var/adm: lp:x:71:8:Line Printer Admin:/usr/spool/lp: smtp:x:0:0:Mail Daemon User:/: uucp:x:5:5:uucp Admin:/usr/lib/uucp: nuucp:x:9:9:uucp Admin:/var/spool/uucppublic:/usr/lib/uucp/uucico ...