useful commandswhich, whereisenv 1su -- a word of wisdomroot: su and sudomotivation for rootmotivation for not having rootsusudo 2Starting LinuxHardware self diagosticsLinux kernel loaded from /boot directory of root deviceKernel starts running and initializes itselfKernel starts process init pid = 1first user process3Run LevelsLinux kernel can run in different ways, defined by run levels. 10 levels define desired state of the systemview /etc/inittab (sidenote: what is the difference vi != view)This file describes how the INIT process should set up the system in a certain run-level.4Run Levelsfrom inittab:# Default runlevel. The runlevels used by RHS are:# 0 - halt (Do NOT set initdefault to this)# 1 - Single user mode# 2 - Multiuser, without NFS (The same as 3, if you do not have networking)# 3 - Full multiuser mode# 4 - unused# 5 - X11# 6 - reboot (Do NOT set initdefault to this)5init processinit processfirst user processparent to all processesinit starts other programscontrols run level and boot script associated with each run level6Boot Scriptsscripts:src.sysinitrc.bootrc.modulesrc.localscripts for different run levels located in /etc/rc.dtake a look7Stopping LinuxPull the plug? @#$%^!!!shutdownhaltsync - flush file system
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