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Introduction to UNIX for Web Developers
The Password File  
As far as UNIX is concerned, you "are" your entry in the password file that is usually stored as "/etc/passwd". Some security conscious sysadmins hide the file elsewhere, but there is a good chance that you can find the "passwd" file on your system if you do "cd /etc" then issue and "ls" command.

The password file contains single line entries for each user of the system. Each line contains 7 fields delimited by a colon ":" character that define you in a security sense. A sample line is shown below:

selena:B8776ERDS:42:101:Selena Sol:/usr/home/selena:/usr/bin/tcsh

The fields correspond to the following index:

Field Explanation
username Username for logging in
password Encrypted Password or either an "x" or "*" character to specify that the password is stored in a shadow file for heightened security
userid A number that identifies you uniquely to the UNIX system internals.
groupid A number that specifies your login group. We'll discuss this in just a bit
Comment This field can be used to store any info desired by the sysadmin. Usually it contains your name, but it can contain any desired text.
home directory This is the location of your home directory (where you arrive when you first login.)
shell The name of the shell you are using.

Besides the password file, you are also defined by your entry in the group file that we will look at now.

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