Question

Given the following records, please explain what each field means.

1. A record from passwd file:

testaccount:x:1001:1001:This is a test account:/home/testaccount:/bin/bash

2. A record from shadow file:

testaccount:$6$rRkFTUEC$VJpiBPqh8bABn8I89245f:106691:0:999999:7:::

Answer 1

For the given record,

testaccount:x:1001:1001:This is a test account:/home/testaccount:/bin/bash

testaccount - This is the username of the system.

x - This represent that the passwords encrypted version is stored in the shadow folder

1001 - This is the UID ( User ID), 0-999 are reserved by the administrator and 0 is given for root.

1001 -​​​​​ This is the group ID ( GID ) of the user in this system.

This is a test account - Here we have the User's information in details like name, number etc based on whatever have been stored on the system

/home/testaccount - This is the home directory of the user, it will be a absolute address Starting from root directory

/bin/bash - Absolute path of the command, most commonly it's the shell that it refers to but it doesn't necessarily has to be.

Now for the same data record, from the shadow file of the same password field.

testaccount:$6$rRkFTUEC$VJpiBPqh8bABn8I89245f:106691:0:999999:7:::

testaccount - User name on the system for the user

$6$rRkFTUEC$VJpiBPqh8bABn8I89245f - This is the encrypted password of your and the first $6$ represent that the encryption standard is SHA-512 There is a table for this in each system.

106691 - Last Password Change ( Update) and it's measured as Days since Jan 1, 1970 that password was last changed

0 - The minimum number of days required between password changes. This is usually 0 only.

999999 - The max number of days the password is valid (after that user is forced to change his/her password). This number represent that there is no limit.

7- This is the warning buffer, it's like 7 days before your password is going to expire you'll be warned about it

Rest two : : : which aren't present are the number of days after Password expiring we'll wait to disable the account. And The absolute expiration date of password.

Some of the Feild don't seems to be useful for a single personal system but are very useful in a industrial set up.

Hope it helps.