Linux shutdown command comparison

Linux shutdown command comparison 1. shutdownwww.2cto. comshutdown command safely shut down the system. It is very dangerous for some users to disable linux by directly disconnecting the power supply. Because linux and windows are different, many processes are running in the background, so the force shutdown may be... Linux shutdown command comparison 1. shutdown www.2cto.com shutdown command safely shut down the system. It is very dangerous for some users to disable linux by directly disconnecting the power supply. Since linux and windows run many processes in the background, forced shutdown may lead to data loss in the process? Make the system unstable? In some systems, hardware is damaged. And use the shutdown command before the system is shut down? The system administrator notifies all logged-on users that the system will be disabled. And the login command will be frozen? That is, new users cannot log on again. Is it possible to directly shut down or wait for a certain period of time to shut down? It may also restart www.2cto.com. This is determined by the signal that all processes receive from the system [signal. Does this allow programs like vi to have time to store the files currently being edited? Programs such as mail and news can leave normally. Shutdown is to send a signal [signal] to the init Program? It is required to change the runlevel. Runlevel 0 is used to stop [halt 〕? Is runlevel 6 used to reactivate the [reboot] system? Runlevel 1 is used to bring the system into a state where management work can be performed? Is this preset? Assume that no-h or-r parameter is set to shutdown. Do you want to know what actions are performed during the shutdown (halt) or re-boot (reboot) process? You can view the runlevels related information in the/etc/inittab file. Shutdown parameter description: [-t] before changing to another runlevel? Tell init how long it will take to shut down. [-R] restart the calculator. [-K] isn't it true to shut down? Only a warning signal is sent to each login 〕. [-H] power off after shutdown [halt 〕. [-N] no init? Instead, shut down the server by yourself. Are you not encouraged to use this option? In addition, the consequences of this option are not always what you expected. [-C] cancel current process cancels the currently running shutdown program. So this option certainly does not have a time parameter? But can I enter a message for explanation? This information will be sent to each user. [-F] ignore fsck when restarting calculator [reboot. [-F] forces the fsck when restarting the calculator [reboot. [-Time] set the time before shutdown. 2. halt-the simplest command to shut down halt is to call shutdown-h. When halt is executed? Killing an application process? Execute sync system call? After the file system writes, the kernel is stopped. Parameter description: [-n] prevents sync system calls? After fsck is used to fix the root partition? To prevent the kernel from overwriting the repaired superblock with the old version of superblock. [-W] isn't it a real restart or shutdown? Write the wtmp (/var/log/wtmp) record. [-D] do not write the wtmp record [included in option [-n 〕. [-F] force shutdown or restart without calling shutdown. Before [-I] shutdown [or restart? Disable all network interfaces. [-P] This option is the default option. That is, power off is called during shutdown. 3. how does rebootreboot work like halt? But does it cause host restart? While halt is shut down. 4. is initinit the ancestor of all processes? Its process number is always 1? So sending the TERM signal to init will terminate all user processes? Daemon. Shutdown uses this mechanism. Init defines eight runlevels, and init 0 indicates shutdown? Init1 indicates restart. 5. power off