Linux,Runlevels,Linux,systems, computer Linux Runlevels
Gone are those times when the companies and the organisations didn't need a hi-tech system to handle them. Owing to the considerable increase in the business sector and thus, an enormous increase in the complexity of the organisational struc ----------------------------------------------------------Permission is granted for the below article to forward,reprint, distribute, use for ezine, newsletter, website,offer as free bonus or part of a product for sale as longas no changes a
Linux systems today generally use eight runlevels. Runlevelsdefine what services or processes should be running on thesystem. The init process can run the system in one of eightrunlevels. The system runs only one of the eight runlevelsat a time. The main runlevels are from 0 6. Here's whateach runlevel is forRunlevel 0: Halt System - To shutdown the systemRunlevel 1: Single user modeRunlevel 2: Basic multi user mode without NFSRunlevel 3: Full multi user mode (text based)Runlevel 4: unusedRunlevel 5: Multi user mode with Graphical User InterfaceRunlevel 6: Reboot SystemRunlevels 1 and 2 are generally used for debugging purposedonly, and are not used during normal operations. Most desktoplinux distributions boot into runlevel 5, which starts up theGraphical Login Prompt. This allows the user to use the systemwith X-Windows server enabled. Most servers boot into runlevel3, which starts the text based login prompt.Linux runlevels can be changed on the fly using the init tool.If you want to switch from text based operations to theGraphical Interface, you just have to type in 'telinit 5' in theroot prompt. This will bring up the Graphical Interface in yoursystem.Each runlevel can be configured by the system administrator. The"/etc/inittab" file has information on which runlevel to startthe system at and lists the processes to be run at each runlevel.Each runlevel has its own directory structure where you candefine the order in which the services start. These directoriesare located in the /etc/rc.d/ directory, under which you haverc1.d, rc2.d, rc3.d . rc6.d directories where the number from0 through 6 that corresponds to the runlevel. Inside each directoryare symbolic links that point to master initscripts found in/etc/init.d or /etc/rc.d/init.d.You can also change the runlevel at boot time. If your system usesLILO as the boot manager, you can append the runlevel to the bootcommand :LILO: linux 3 orLILO: linux 5If your system uses GRUB, you can change the boot runlevel bypressing the `e' key to edit the boot configuration. append therunlevel to the end of the boot command as shown:kernel /vmlinuz ro root=/dev/hda1 5
Linux,Runlevels,Linux,systems,