For 2023 - we are now fully retired from IT training.
We have made many, many friends over 25 years of teaching about Python, Tcl, Perl, PHP, Lua, Java, C and C++ - and MySQL, Linux and Solaris/SunOS too. Our training notes are now very much out of date, but due to upward compatability most of our examples remain operational and even relevant ad you are welcome to make us if them "as seen" and at your own risk.
Lisa and I (Graham) now live in what was our training centre in Melksham - happy to meet with former delegates here - but do check ahead before coming round. We are far from inactive - rather, enjoying the times that we are retired but still healthy enough in mind and body to be active!
I am also active in many other area and still look after a lot of web sites - you can find an index ((here))
What Linux run level am I in?
Linux / Unix systems have a "run level" that they're in ...
0 - halted
1 - single user
2 - multiuser (client)
3 - full multiuser
5 - full multiuser with X windows running
6 - reboot
How do I find out what run level a system is in at the moment?
- a question asked on today's Java course (OK - it was over lunch and we were
off topic ...)
1. The runlevel
command tells you what run level you are in
2. The who -r
command also tells you the run level, together with some other information.
Here's a machine which is in full multiuser mode, running as a server:
[trainee@melksham ~]$ /sbin/runlevel
[trainee@melksham ~]$ who -r
run-level 3 2009-05-15 09:28 last=S
And here's one which is in full multiuser mode and has the windows system running too ...
[trainee@easterton ~]$ /sbin/runlevel
[trainee@easterton ~]$ who -r
run-level 5 2009-05-15 15:04 last=S
1. The runlevel
command is intended for administrators only, so is in the sbin
directory which is not on the normal user's path. However, the command is purely information so is available to all users who know where to find it.
2. The default run level of a system can be changed by updating the /etc/inittab
file ... the line
will bring the system up into run state 5 on startup / reboot. Change the 5 to a 3 if you want the machine to start / reboot into run state 3
3. It is strongly recommended that you do not run your web servers in run state 5 ... I have had instances on a course where delegates have complained about a slow server, and they have been amazed when I have walked up to a 'spare' machine, moved the mouse around, and asked if the performance has improved. They have been even more amazed to be able to confirm that it HAS made a difference. What had happened? The system was running a screen saver in X Windows ... and it was eating up all the cpu resource in keeping an "atlantis" display of 3D whales and sharks swimming around the screen. Moving the mouse cancelled the screen saver ... and released the resources back to the server
4. Rather obviously, runlevel
cannot report that a machine is in run state 0! (written 2009-05-15)
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articlesA164 - Web Application Deployment - Services and Regular Jobs 
Repeating tasks with crontab - (2005-12-27) 
Browser -> httpd -> Tomcat -> MySQL. Restarting. - (2006-10-28) 
Linux / Unix - process priority and nice - (2007-01-10) 
Linux run states, shell special commands, and directory structures - (2007-08-03) 
Automatic startup and shutdown of Tomcat - (2008-02-24) 
Changing a screen saver from a web page (PHP, Perl, OSX) - (2008-05-06) 
FTP server on Fedora Linux - (2008-07-06) 
Apache httpd, MySQL, PHP - installation procedure - (2008-08-01) 
memcached - overview, installation, example of use in PHP - (2008-08-02) 
Dialects of English and Unix - (2008-08-21) 
daemons - what is running on my Linux server? - (2008-11-23) 
Using the internet to remotely check for power failure at home (PHP) - (2009-04-29) 
What are .pid files? - (2010-10-23) 
On time - (2011-01-23) 
The Kernel, Shells and Daemons. Greek Gods in computing - (2012-07-01) 
Managing daemons from a terminal session - (2012-07-01) 
Starting MySQL. ERROR! The server quit without updating PID file - how we fixed it. - (2015-05-06)
Some other Articles
An FAQ on the Apache httpd and Apache Tomcat web servers, and on using them togetherAbstract Classes - JavaChoosing the right version of Java and TomcatServlet life cycle, and Java Servlet variable scopeWhat Linux run level am I in?You cannot please all of the people all of the timePatterns in numbers - room occupancyOffers that I can refuseMelksham Candidates for Wiltshire Unitary ElectionPreventing forum spam - checks at sign up
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This is a page archived from The Horse's Mouth at
the diary and writings of Graham Ellis.
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