Busybox halt vs poweroff. Thank you, Ankur. On modern kernels, writing appropriate strings to /sys/power/state is the primary mechanism to trigger this suspend. The BusyBox init executes OpenRC runlevel scripts according to entries in /etc/inittab. 6. See kernel documentation for details. 00-pre3 was configured without init, but with poweroff, halt and reboot. h下的halt/poweroff/reboot可知，实现都在halt_main ()中。 下 指令 halt、poweroff、跟 reboot 的動作過程類似，都是 kill pid=1 的行程，一般是 init，pid=1 的行程會去執行 inittab 的 shutdown 動作後，呼叫函式庫函式 reboot ()。reboot () 再執行系統呼叫進到 kernel 執行 sys_reboot () ，去做相關動作。 Signal的表格如下所示: 指令 halt、poweroff、跟 reboot 的動作過程類似，都是 kill 1 號行程，一般是 init，在 OpenWrt 是 procd。1 號行程會去執行 inittab 的 shutdown 動作後，呼叫函式庫函式 reboot()。reboot() 再執行系統呼 coral busybox c74f1d2cb48c6a9216ea901178e43c02ac7da0dc. 04. --halt Halt the machine, regardless of which one of the three commands is invoked. c file log blame Buildroot uses busybox-1. First, loginctl poweroff isn't a thing. This topic was discussed 2 文章浏览阅读7k次，点赞4次，收藏8次。关机命令：1、halt 立刻关机 2、poweroff 立刻关机 3、shutdown -h now 立刻关机 (root用户使用) 4、shutdown -h 10 10分钟后自动关机 如果是通过shutdown命令设置关机的话，可以用shutdown -c命令取消重启重启命令：1、reboot 2、shutdown -r now 立刻重启 (root用户使用) 3、shutdown -r 1 -r --reboot Reboot the machine -h Equivalent to --poweroff, overridden by --halt -k Don't halt/power-off/reboot, just send warnings --no-wall Don't send wall message before halt/power-off/reboot -c Cancel a pending shutdown For your future reference, most commands can be described with their modifiers by entering the Code: Select all --help 关键词：halt/poweroff/reboot、reboot ()、SIGUSR1/SIGTERM/SIGUSR2等。 1. NAME ¶ BusyBox - The Swiss Army Knife of Embedded Linux SYNTAX ¶ busybox <applet> [arguments] # or <applet> [arguments] # if symlinked DESCRIPTION ¶ BusyBox combines tiny versions of many common UNIX utilities into a single small executable. What is the difference between Halt and Poweroff commands? I understand that both of them lead to shutdown of the machine, then why 2 commands? I want to know this because in my Virtual Machine. 18. BUSYBOX man page. The ‘systemctl’ and the ‘shutdown’ commands allow you to power-off, halt, reboot, suspend and hibernate your Linux system. 04，当一切都配置完毕以后，我就在terminal 里输入了 halt 命令，结果机器关到一半就死机了，所以我不得不… 显示全部 关注者 67 It is possible to directly inform the in-kernel software suspend code (swsusp) to enter a suspended state; the exact method and state depends on the level of hardware support. So, again, there's no difference (absent --force) between the halt command and and shutdown command (with the equivalent option) in this toolset. Do not contact the init system. BusyBox mirror. 5-1ubuntu4) built-in shell (ash) Enter 'help' for a list of built-in commands. But the last three commands doesn't work without init. reboot reboot的工作过程差不多跟halt一样﹐不过它是引发主机重启﹐而halt是关机。 它的参数与halt相差不多。 4. Contribute to mirror/busybox development by creating an account on GitHub. I used poweroff -f because poweroff with no parameters doesn't do anything. halt, poweroff, reboot may be used to halt, power-off or reboot the machine. Did you strip it for filesize reasons? Reboot works and is listed in busybox 4. Dec 16, 2025 · When /sbin/poweroff is executed (I killed my processes just before calling it), board takes around 5s to power-off. A compilation of Linux man pages for all commands in HTML. Also, ash does have an exit command, but the resource you mentioned is for the busybox binary, not the shell. The poweroff command tells it shutdown completely - the same as if you selected Power Off from within ADM. It provides minimalist replacements for most of the utilities //kbuild:lib-$ (CONFIG_HALT) += halt. reboot命令端 执行reboot命令，busybox检查当前命令为reboot，进入函数halt_main， reboot，halt和poweroff都会进入这个函数，不同的命令发送的信号和执行的操作不同。 现只分析reboot的情况。 代码如下 BusyBox combines tiny versions of many common UNIX utilities into a single small executable. BusyBox v1. Hi List, for an embedded system (vdr) I don't need a real init. It sends an ACPI command to the board, then to the PSU, to cut the power. BusyBox Commands Table of Contents Available BusyBox Commands basename cat chgrp chmod chown chroot chvt clear cp cut date dc dd df dirname dmesg du dumpkmap echo expr false fbset fdflush find free freeramdisk grep gunzip gzip halt head hostname id init insmod kill killall ln loadfont loadkmap logger ls lsmod md5sum mkdir mkfifo mknod mkswap more mount mv nc nslookup ping poweroff For example, type systemctl halt or systemctl poweroff to achieve similar results to the shutdown command. How is it possible to tell the BusyBox init to shut down all services probably by calling /etc/rc. 5 (Ubuntu 1:1. OUTPUT: A) Reboot [root@ (none BUSYBOX man page. busybox. Does someone has a solution? BTW. A multi-call binary is an executable program that performs the same job as more than one utility program. -p, --poweroff Power-off the machine, regardless of which one of the three commands is invoked Foreword Be aware that, busybox tries to imitate popular feature extensions from GNU's implementation of programs and utilities, though busybox often differs from GNU's implementation in subtle ways. o //usage:#define halt_trivial_usage //usage: " [-d DELAY] [-n] [-f]" IF_FEATURE_WTMP (" [-w]") //usage:#define halt_full_usage "\n\n" //usage: "Halt the system\n" //usage: "\n -d SEC Delay interval" //usage: "\n -n Do not sync" //usage:#define halt_trivial_usage //usage: " [-d DELAY] [-n] [-f]" IF_FEATURE_WTMP (" [-w]") //usage:#define halt_full_usage "\n\n" //usage: "Halt the system\n github sync of BusyBox source from git://git. A runlevel is basically a collection of services that needs to be started when certain conditions are met. May 2, 2025 · In this article, we’ll explain the difference between the shutdown, poweroff, halt, and reboot commands in Linux with practical examples. On board when I run reboot or halt or poweroff, it gives me the prompt back without doing anything. net/busybox - asac/busybox The Swiss Army Knife of Embedded Linux - private tree - busybox/init/halt. (initramfs) A manual fsck solves the problem, but I need to know which partition got corrupted. 普通的reboot是通过busybox为入口，进入halt_main函数，然后给init进程发送SIGTERM信号，init进程… This command is asynchronous; it will return after the power-off operation is enqueued, without waiting for it to complete. apparently reboot is just a link to systemctl? (I'm using arch) So how does this work? init poweroff works and stuff, but reboot / poweroff just seems to be linked to systemctl man reboot ： reboot -f, --force Force immediate halt, power-off, reboot. init halt. . But ignoring that Why are so many commands for some simple tasks like powering off the system? You will actually find that shutdown, poweroff, reboot, halt, telinit, and so on, are all just symlinks to systemctl. This is a more direct method for shutting down the system compared to halt, as it focuses on powering down all components. All Unifi SSH Commands that you need to know. o //kbuild:lib-$ (CONFIG_REBOOT) += halt. reboot Shut down and reboot the system. To learn more about these commands, feel free to visit their respective ‘man’ pages. busybox 1. I built a testing environiment in which '/bin/init' is only a shell script, which loads some drivers and starts the main application. 7. Jun 1, 2025 · Linux halt, reboot, and poweroff commands with detailed examples. 7. OPTIONS The following options are understood: --help Print a short help text and exit. Systemd has `halt poweroff reboot shutdown` options which all link to /bin/systemctl. c blob: f69b897723a83d08562acc563cd28ccb2f275e5f (plain) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 The poweroff, shutdown -h now, and halt -p commands all do the same thing as halt alone, while additionally sending an ACPI command to signal the power supply unit to disconnect the main power. Jul 2, 2019 · halt/poweroff/reboot三个busybox命令，分别对应RB_HALT_SYSTEM (0xcdef0123)/RB_POWER_OFF (0x4321fedc)/RB_AUTOBOOT (0x01234567)。 这三个命令的区，详细可以参考kernel_halt ()、kernel_power_off ()、kernel_restart ()。 Sep 25, 2024 · The poweroff command sends an ACPI signal to the system, instructing it to power down. If you like the content, we would appreciate your support by buying us a coffee. systemd is more accurate here, and halt results in halting the machine only (leaving power on), and poweroff is required to actually power it off. Get more information out of your Unifi devices with these commands ubirename busybox udhcpc busybox uevent busybox umount busybox uname coreutils unexpand coreutils uniq coreutils unix2dos busybox unlink coreutils unlzma busybox unlzop busybox unpigz pigz unxz busybox unzip busybox uptime coreutils users coreutils usleep busybox uudecode busybox uuencode busybox vconfig busybox vdir coreutils vi busybox vlock Note: See TracBrowser for help on using the repository browser. With your typical Linux shutdown command, what is the difference between halting the system and powering off the system? BusyBox mirror. 0 functions. 3. What is the safest way to shutdown the cam with a path: root / init / halt. poweroff is exactly like halt, but it also turns off the unit itself (lights and everything on a PC). 关键词：halt/poweroff/reboot、reboot ()、SIGUSR1/SIGTERM/SIGUSR2等。 1. BusyBox is an open source (GPL) project providing simple implementations of nearly 400 common commands. It provides minimalist replacements for most of the utilities you usually find in GNU coreutils, util-linux, etc. 9 I get the (initramfs) prompts/busybox occasionally in Ubuntu 20. -p, --poweroff Power-off the machine, regardless of which one of the three commands is invoked The difference between halt and poweroff is that in halt mode the control is returned to a "ROM monitor" (think BIOS), whereas poweroff simply powers the system board off. Also again, option-less shutdown now (which none of halt, reboot, or poweroff can end up invoking as they all set options) brings the system into single user mode rather than shutting it down. d/xxx stop on calling the BusyBox applets "poweroff", "halt" or "reboot"? I'm trying to write an init, but can't figure out the reboot\poweroff thing. 2. Thank you so much for your visit and support. On board reboot,halt and poweroff links to busybox. -H or –halt for halt -P or –poweroff for poweroff -R or –reboot for reboot After exploring the historic commands for stopping and restarting a system, let’s bring them all together. 12 It’s poweroff or poweroff -f. I would like to reduce this delay but I need to take care that no data is corrupted or missing after reboot. 本文深入剖析init、halt、shutdown等Linux关机命令的本质区别，通过解析其底层调用关系、执行流程与适用场景，助您彻底理解关机机制，从而做出最安全的系统操作决策。 For reference, these are the more useful threads I've read on the halt vs shutdown discussion, though they haven't really discussed modern uses for halt implementations that shutdown the OS without powering off the system: I was looking for the same, and my BusyBox installation doesn't have shutdown, restart or reboot commands. o //kbuild:lib-$ (CONFIG_POWEROFF) += halt. So WOL would take as long as normally takes to boot from cold. OS Stop Control At this point, the names of stop commands can just be semantically different, while the underlying code paths remain basically the same. busybox下的halt/p Here’s what might be displayed before the screen goes dark: Broadcast message from root@localhost The system is going down for power off NOW! Use case 2: Halt the system (same as halt) Code: Chapter 3. The utilities in BusyBox Note that on many SysV systems halt used to be synonymous to poweroff, i. poweroff：此 命令 具备关机功能，通过向系统发送相关信号来正常终止全部应用进程，进而完全切断计算机电源。 相较于halt linux 关机指令，poweroff更具安全性和可靠性优势。 如何正确地使用关机指令 在使用关机指令时，用户需要注意以下几点： The systemd init system provides additional commands that perform the same functions; systemctl poweroff does the same thing that 'shutdown -P' does. Understand system operations for stopping, powering down, or rebooting in the command line. Linux 下 halt, poweroff, shutdown 有什么区别？ 今天刚刚装了 Ubuntu 12. init init是所有进程的祖先﹐它的进程号始终为1﹐所以发送TERM信号给init会终止所有的用户进程﹑守护进程等。 shutdown就是使用这种机制。 USAGE BusyBox is a multi-call binary. both commands would equally result in powering the machine off. > denotes command input, and a line without the prefix denotes the output from that command. The main disadvantage of using systemctl is losing the ability to schedule or cancel the shutdown process. The difference between halt and poweroff is that in halt mode the control is returned to a "ROM monitor" (think BIOS), whereas poweroff simply powers the system board off. which leads to a poweroff: applet not found message. e. Kindly waiting for your suggestions. When I run "reboot -f" it gives following message and my board gets hang. That means there is just a single BusyBox binary, but that single binary acts like a large number of utilities. busybox下的halt/poweroff/reboot实现 通过applets. This command honors --force and --when= in a similar way as halt. c at master · brgl/busybox 三、代码详解 1. They are 'backward compatibility shims' mapping to a single program. BusyBox combines tiny versions of many common UNIX utilities into a single small executable. This allows BusyBox to be smaller since all the built-in utility programs (we call them applets) can share code for many common operations. ujwrs, yekgt, 1dqlb3, wkjmz, epvrzx, yktxi, dndt0e, 4upc5y, 9rjb, gf88,