i Linux Basic – part 3 – All things in moderation

Linux Basic – part 3

5. Users inside of Linux

Let’s talk about users inside of Linux. The users inside of Linux are stored inside the /etc/passwd file. So here is what the contents of the /etc/passwd file look like:

So, let’s try to understand what the sample entry means. The output for the first line look like this :

root:x:0:0:root:/root:/bin/bash

• The “root” is the username.
• The root is followed by x, which means that the passsword is moved inside the shadow file, which we will discuss next
• Next is the UID of user, which (0) for root, followed by the groupid(0) primary group the user belongs to. In this case, the use belongs to root.
• Next is the space for comments, which an administrator may want to store.
• It is then followed by the absoulute path of the home directory, which is also the starting localtion of the command line.
• In a standard /etc/passwd file , most of the users would be default users like bin/adm and mail
• All the Unix/Linux Users are identifed by a user id, which starts at 0 and increments from there with some jumps in between. Any user with uid 0 has root level privileges.
• The nondefault users gernerally have UID starting from 500 or 1000, and increment from there.
• Inside of the /etc/passwd file , some users would have /false at the end, which means theat thore users cannot have an interactive login session.
6. Linux Services

The tranditional Linux services are inside the /etc/init.d directory; this would include srcripts to execute a particular service or program that would begin when Linux starts loading.