Exercises, examples and other material relating to training module A161. This topic is presented on public courses Deploying LAMP - Linux, Apache, MySQL, Perl/PHP
, Linux Administration
, Deploying Java Applications on Linux / Unix
, Linux bootcamp
Linux is a true multiuser operating system. Each file and process is owned by a specific user and is accessible to others based on group and world permissions. In this module you'll learn how to create, monitor and secure user accounts and control user processes. You'll also learn about the all powerful root account and how to use it for such tasks as resetting regular user's passwords.
Related technical and longer articlesA Web interface for your Linux admin tasks
|Articles and tips on this subject||updated|
|4045||Linux Web Server - User Roles, User Accounts, and shared administration|
There are many different roles associated with setting up and running a web site and it's unlikely that they'll all be undertaken by the same person.
• Server administrator
• Web site developer
• Web site administrator
• Web site user
And each of them has their own areas of authority, ...
|2639||su or su - ... what is the difference?|
If you're wanting to do admin work on a Unix or Linux system, you'll probably need to be logged in as the administrator. However, you're likely to find that you're not allowed to log in as root directly, and that you have to use the su command. Strictly speaking, "su" stands for "Substitute User" and ...
|2491||Root is root for a reason!|
A busy day ... major update to the Chamber of Commerce Site, and a heart-stopping moment when I realised that we had moved our server's clock forward by a year instead of by a few minutes. A few log files have some funny time stamps in them, and web stats will look odd for a while ... and there was ...
I asked who I was logged in as yesterday ... and I got two different answers:
[melksham ~]# who am i
trainee pts/1 2009-07-21 13:16 (192.168.200.80)
[melksham ~]# whoami
When you log in to a Unix or a Linux box, you give an account name (and password, I hope!) and you're ...
|2203||Always use su with minus. And where do programs come from?|
When you're using the su command to do systems admin work as route, you should always add the - options (minus sign on its own) to start a new root environment too. This means that the PATH that executable files are found from is replaced (amongst other things) - so you can find things like ifconfig ...
|2117||Choosing a railway station fairly in PHP|
I've been transferring the West Wilts Rail Users Group web site into a wiki this evening ... and came up with the question "How do I fairly choose which station to put on their front page".
Of course, I favour Melksham. It's far and away the one that needs all the help and support it can get from ...
|2103||Ask the Tutor - Open Source forum|
Well - I've taken the plunge!
When I installed a YaBB forum some seven years ago, I never imagined that it would grow as big as it did, with hundreds of posts on each of the subjects covered. And with that growth came growth panes where the forum became "Pot Bound" - unable to grow any further. So, ...
|1902||sstrwxrwxrwx - Unix and Linux file permissions|
Have you ever wondered about those letters that turn up on the left of a long listing (ls -l) report? Here's an example:
drwxrwxrwt 8 root wheel 272 17 Nov 2007 Shared
drwxr-xr-x 14 chris ellis 476 29 Sep 2007 chrise
drwxr-xr-x 270 graham ellis 9180 23 Nov 07:25 grahame
drwxr-xr-x 34 lisa ellis 1156 27 Sep 06:44 lisae
drwxr-xr-x 29 trainee trainee 986 5 Sep 03:55 trainee
-rw-rw-r-- 1 graham ellis 294 23 Nov 07:41 uu
-rw-r----- 1 graham ellis 922 21 Nov 08:45 wb
-rw------- 1 graham ellis 5143 23 Nov 07:25 xx
|1904||Ruby, Perl, Linux, MySQL - some training notes|
We have just come to the end of a solid 12 days of training ... and we are just getting ready for the next week, with delegates arriving this evening. There's a lot going on behind the scenes, even over this weekend, with the hotel to be prepared as well as the training course. (Picture - our clean ...
|1773||The Longest Possible Day|
I post here every day - or I try to at least. What is the longest possible gap between posts for me to leave, and still achieve that? Well - it's 48 hours and I'm very close to that today.
Not that it's been quiet - in fact I had my head down yesterday, taking a whole lot of pages that we transferred ...
|1650||Looking for files with certain characteristics (Linux / Unix)|
I was about to use chown to change the ownership of an entire subdirectory tree that had been passed from one user to another. But - hang on - were there any files there that belonged to someone else for any reason? One way to find out - a find command:
find . -not -user savethetrain -print
|1619||User and Group settings for Apache httpd web server|
When you're running an Apache httpd web server, you should run it using a separate daemon user account and group set up for the purpose and not run it as either root (a horrific thing to do, as it would lead to all sorts of security holes) or nobody (another very bad idea, as the "nobody" applications ...
|1592||Setting up a new user - Linux or Unix|
Creating a local user account on a Linux box:
1. Add an entry to /etc/passwd
2. Add an entry to /etc/shadow
3. Add an entry to /etc/group IF the user is in a new group
4. Use the passwd command to set the user's password
5. Create the user's home directory
6. Change the ownership of the user's home ...
|409||Functions and commands with dangerous names|
There are some words that we use in our day to day programming life that seem a little scarey and inappropriate to their real task ... and sometimes those words worry trainees on our courses. Examples:
PHP's reset function. It's name seems to threaten to clear our data from somewhere, but all it does ...
Some modules are available for download
as a sample of our material or under an Open Training Notes License
for free download from [here]
Topics covered in this module
What are users and groups?.
The root account.
Real and effective id.
Adding and managing user accounts.
Setting up a user account.
Ownership and permissions, files and processes.
Control of processes.
If you are looking for a complete course and not just a information on a single subject, visit our Listing and schedule
Well House Consultants specialise in training courses in
Linux and LAMP
. We run
throughout the UK (and beyond for longer courses), and
at our training centre in Melksham, Wiltshire, England.
It's surprisingly cost effective to come on our public courses -
even if you live in a different
country or continent to us
We have a technical library of over 700 books on the subjects on which we teach.
These books are available for reference at our training centre.