I was wondering what have debian into my system, which i think some of the stuff i do not want, i just want to save my RAM, coz i discover that my linux seems to be jerky.
I found this pagehttp://www.techworld.com/opsys/features/index.cfm?featureid=294&Page=1&pagePos=16
The page might be obsolete, so i do want to code the important part
When it starts up, Linux looks at its startup directories to see what services to fire up. All Unix family operating systems have the concept of a "runlevel", which is the state to which the system boots.The two most common runlevels are 3 (standard multi-user mode with a command line prompt on the console screen) and 5 (multi-user mode with a graphical X-Windows user interface). You can see which runlevel your system is operating in by looking in /etc/inittab;you'll see an "initdefault" line that looks something like:
I investigate my ubuntu, the default runlevel for me is 2, the user of this page is red hat user i suppose.
Linux's startup files live in a set of directories under /etc/rc.d. The actual startup scripts themselves live in /etc/rc.d/init.d,and the directories that relate to the various runlevels have symbolic links (like Windows shortcuts) to these main scripts.
Each runlevel has a directory within /etc/rc.d – these are called rc1.d, rc2.d, and so on – the number relates to the runlevel.So for runlevel 5, we care about the contents of /etc/rc.d/rc5.d.
Instead, for debian, runlevel script store directly in /etc such as /etc/rc0.d till /etc/rc5.d
If you want to disable something in your current runlevel,you'll need to change its "S" script to a "K" script. The trick here is to figure out what you need to change the ordering to – for instance, Sendmail starts up as S80sendmail, but stops as S30sendmail. The trick is to look in the runlevel 0 (halt) directory, as this shuts down pretty well everything, for a "K" script from which you can crib the appropriate number. So let's assume we want to stop the CUPS (printing) service from running. Its startup script in /etc/rc.d/rc5.d is called S90cups, so let's do a quick scan for items in /etc/rc.d/rc0.d that are called K??cups:
That is cool, i think i will try it tonight.