File:  [NetBSD Developer Wiki] / wikisrc / guide / boot.mdwn
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Fri Mar 1 13:05:53 2013 UTC (8 years, 7 months ago) by jdf
Branches: MAIN
CVS tags: HEAD
 * Add boot chapter of the guide
 * update my personal page for pages already done

    1: # The first steps on NetBSD
    2: 
    3: After installing and rebooting, the computer will boot from the hard disk. If
    4: everything went well, you'll be looking at the login prompt within a few seconds
    5: (or minutes, depending on your hardware). The system is not yet fully
    6: configured, but basic configuration is easy. You will see how to quickly
    7: configure some important things, and in doing so you will learn some basics
    8: about how the system works.
    9: 
   10: ## Troubleshooting
   11: 
   12: ### Boot problems
   13: 
   14: If the system does not boot it could be that the boot manager was not installed
   15: correctly or that there is a problem with the *MBR* (*Master Boot Record*). Boot
   16: the machine from your install medium (CD, DVD, floppy, etc.) and when you see
   17: the boot menu, select the option to drop to the boot prompt.
   18: 
   19:     type "?" or "help" for help.
   20:     > ?
   21:     commands are:
   22:     boot [xdNx:][filename] [-12acdqsvxz]
   23:          (ex. "hd0a:netbsd.old -s")
   24:     ls [path]
   25:     dev xd[N[x]]:
   26:     consdev {pc|com[0123]|com[0123]kbd|auto}
   27:     modules {enabled|disabled}
   28:     load {path_to_module}
   29:     multiboot [xdNx:][filename] [<args>]
   30:     help|?
   31:     quit
   32:     > boot hd0a:netbsd
   33: 
   34: The system should now boot from the hard disk. If NetBSD does not boot correctly
   35: from the hard disk, there is probably a Master Boot Record problem. You can
   36: install the boot manager or modify its configuration with the **fdisk -B**
   37: command. See [[Installing the boot manager|guide/misc#bootmanager]] for a
   38: detailed description.
   39: 
   40: ### Misconfiguration of `/etc/rc.conf`
   41: 
   42: If you or the installation software haven't done any configuration of
   43: `/etc/rc.conf` (sysinst normally will), the system will drop you into *single
   44: user mode* and show the message
   45: 
   46:     /etc/rc.conf is not configured. Multiuser boot aborted
   47: 
   48: When the system asks you to choose a shell, simply press `RETURN` to get to a
   49: /bin/sh prompt. If you are asked for a terminal type, respond with `vt220`
   50: (or whatever is appropriate for your terminal type) and press RETURN. You may
   51: need to type one of the following commands to get your delete key to work
   52: properly, depending on your keyboard:
   53: 
   54:     # stty erase '^h'
   55:     # stty erase '^?'
   56: 
   57: At this point, you need to configure at least one file in the `/etc` directory.
   58: However, the root file system (`/`) is mounted read-only, so you will first need
   59: to make it writable with:
   60: 
   61:     # mount -u -w /
   62: 
   63: Next, take a look at the `/etc/rc.conf` file. Modify it to your tastes, making
   64: sure that you set `rc_configured=YES` so that you don't end up in this position
   65: again. Default values for the various programs can be found in
   66: `/etc/defaults/rc.conf`. More complete documentation can be found in
   67: [rc.conf(5)](http://netbsd.gw.com/cgi-bin/man-cgi?rc.conf+5+NetBSD-5.0.1+i386).
   68: 
   69: When you have finished, type `exit` at the prompt to leave the single-user shell
   70: and continue with the multi-user boot.
   71: 
   72: ## The man command
   73: 
   74: If you have never used a Unix(-like) operating system before, your best friend
   75: is now the
   76: [man(1)](http://netbsd.gw.com/cgi-bin/man-cgi?man+1+NetBSD-current) command,
   77: which displays a manual page. The NetBSD manual pages are among the best and
   78: most detailed you can find, although they are very technical.
   79: 
   80: A good manual to read after booting a new NetBSD system is
   81: [afterboot(8)](http://netbsd.gw.com/cgi-bin/man-cgi?afterboot+8+NetBSD-5.0.1+i386).
   82: It contains information about various necessary and useful configuration
   83: settings.
   84: 
   85: `man name` shows the man page of the `name` command and `man -k name` shows a
   86: list of man pages dealing with `name`. The tool
   87: [apropos(1)](http://netbsd.gw.com/cgi-bin/man-cgi?apropos+1+NetBSD-current) does
   88: a full-text search on the manpages installed on your system, sorted by
   89: relevance.
   90: 
   91: To learn the basics of the `man` command, type:
   92: 
   93:     # man man
   94: 
   95: Manual pages contain not only information about commands but also descriptions
   96: of some NetBSD features and structures. For example, take a look at the
   97: [hier(7)](http://netbsd.gw.com/cgi-bin/man-cgi?hier+7+NetBSD-5.0.1+i386) man
   98: page, which describes in detail the layout of the filesystem used by NetBSD.
   99: 
  100:     # man hier
  101: 
  102: Other similar pages are
  103: [release(7)](http://netbsd.gw.com/cgi-bin/man-cgi?release+7+NetBSD-5.0.1+i386)
  104: and
  105: [pkgsrc(7)](http://netbsd.gw.com/cgi-bin/man-cgi?pkgsrc+7+NetBSD-5.0.1+i386).
  106: 
  107: Manual pages are divided in several sections, depending on what they document:
  108: 
  109:  1. general commands (tools and utilities), see
  110:     [intro(1)](http://netbsd.gw.com/cgi-bin/man-cgi?intro+1+NetBSD-5.0.1+i386)
  111:  2. system calls and error numbers, see
  112:     [intro(2)](http://netbsd.gw.com/cgi-bin/man-cgi?intro+2+NetBSD-5.0.1+i386)
  113:  3. C libraries, see
  114:     [intro(3)](http://netbsd.gw.com/cgi-bin/man-cgi?intro+3+NetBSD-5.0.1+i386)
  115:  4. special files and hardware support, see
  116:     [intro(4)](http://netbsd.gw.com/cgi-bin/man-cgi?intro+4+NetBSD-5.0.1+i386)
  117:  5. file formats, see
  118:     [intro(5)](http://netbsd.gw.com/cgi-bin/man-cgi?intro+5+NetBSD-5.0.1+i386)
  119:  6. games, see
  120:     [intro(6)](http://netbsd.gw.com/cgi-bin/man-cgi?intro+6+NetBSD-5.0.1+i386)
  121:  7. miscellaneous information pages, see
  122:     [intro(7)](http://netbsd.gw.com/cgi-bin/man-cgi?intro+7+NetBSD-5.0.1+i386)
  123:  8. system maintenance and operation commands, see
  124:     [intro(8)](http://netbsd.gw.com/cgi-bin/man-cgi?intro+8+NetBSD-5.0.1+i386)
  125:  9. kernel internals, see
  126:     [intro(9)](http://netbsd.gw.com/cgi-bin/man-cgi?intro+9+NetBSD-5.0.1+i386)
  127: 
  128: You can read the introduction to each of the sections by reading the `intro`
  129: page of the specific section (in this case, 8):
  130: 
  131:     # man 8 intro
  132: 
  133: A subject may appear in more than one section of the manual; to view a specific
  134: page, supply the section number as an argument to the man command. For example,
  135: `time` appears in section 1 (the time user command) and in section 3 (the time
  136: function of the C library). To see the man page for the time C function, write:
  137: 
  138:     # man 3 time
  139: 
  140: To see all the available pages:
  141: 
  142:     # man -w time
  143:     # man -a time
  144: 
  145: ## Editing configuration files
  146: 
  147: Other than a shell, a text editor is the most essential tool for NetBSD system
  148: administration.
  149: 
  150: Though there is the line-editor
  151: [ed(1)](http://netbsd.gw.com/cgi-bin/man-cgi?ed+1+NetBSD-5.0.1+i386), you might
  152: want to use the other editor provided with the NetBSD base system, named
  153: [vi(1)](http://netbsd.gw.com/cgi-bin/man-cgi?vi+1+NetBSD-5.0.1+i386). There is a
  154: [separate chapter](guide/edit) about using vi. You should read this first, as
  155: editing config files is essentially for using NetBSD.
  156: 
  157: Though vi(1) is *the* standard on Unix systems, you maybe want to get a bit used
  158: to ed(1). vi is an descendant of ed, and the commands used in ed are applicable
  159: for vi as well.
  160: 
  161: ## Login
  162: 
  163: For the first login you will use the `root` user, which is the only user defined
  164: at the end of the installation. At the password prompt type the password for
  165: root that you set during the installation. If you didn't set a password, just
  166: press `Enter`. Note that the password isn't echoed when you type it!
  167: 
  168:     NetBSD/i386 (Amnesiac) (ttyE0)
  169:     login: root
  170:     password:
  171:     We recommend creating a non-root account and using su(1) for 
  172:     root access.
  173:     #
  174: 
  175: ## Changing the `root` password
  176: 
  177: If you did not set a password for `root` during the installation, you should use
  178: the [passwd(1)](http://netbsd.gw.com/cgi-bin/man-cgi?vi+1+NetBSD-5.0.1+i386)
  179: command to do so now:
  180: 
  181:     # passwd
  182:     Changing local password for root.
  183:     New password:
  184:     Retype new password:
  185: 
  186: Passwords are not displayed on the screen while you type.
  187: 
  188: Choose a password that has numbers, digits, and special characters (not space)
  189: as well as from the upper and lower case alphabet. Do not choose any word in any
  190: language. It is common for an intruder to use dictionary attacks.
  191: Nonetheless, you should choose a password you can type independent of the
  192: keyboard layout. When using some special characters, you might have problems
  193: typing it with your local keymap later on.
  194: 
  195: ## Adding users
  196: 
  197: For security reasons, it is bad practice to login as root during regular use and
  198: maintenance of the system. Instead, administrators are encouraged to add a
  199: regular user, add the user to the `wheel` group, then use the
  200: [su(1)](http://netbsd.gw.com/cgi-bin/man-cgi?su+1+NetBSD-5.0.1+i386) command
  201: when root privileges are required. NetBSD offers the
  202: [useradd(8)](http://netbsd.gw.com/cgi-bin/man-cgi?useradd+8+NetBSD-5.0.1+i386)
  203: utility to create user accounts. For example, to create a new user:
  204: 
  205:     # useradd -m joe
  206: 
  207: The defaults for the useradd command can be changed; see the
  208: [useradd(8)](http://netbsd.gw.com/cgi-bin/man-cgi?useradd+8+NetBSD-5.0.1+i386)
  209: man page.
  210: 
  211: User accounts that can `su` to root are required to be in the `wheel` group.
  212: This can be done when the account is created by specifying a secondary group:
  213: 
  214:     # useradd -m -G wheel joe
  215: 
  216: As an alternative, the
  217: [usermod(8)](http://netbsd.gw.com/cgi-bin/man-cgi?usermod+8+NetBSD-5.0.1+i386)
  218: command can be used to add a user to an existing group:
  219: 
  220:     # usermod -G wheel joe
  221: 
  222: In case you just created a user but forgot to set a password, you can still do
  223: that later using
  224: [passwd(1)](http://netbsd.gw.com/cgi-bin/man-cgi?passwd+1+NetBSD-5.0.1+i386):
  225: 
  226:     # passwd joe
  227: 
  228: ### Note
  229: 
  230: You can edit `/etc/group` directly to add users to groups, but do *not* edit the
  231: `/etc/passwd` directly; use
  232: [vipw(8)](http://netbsd.gw.com/cgi-bin/man-cgi?vipw+8+NetBSD-5.0.1+i386).
  233: 
  234: ## Shadow passwords
  235: 
  236: Shadow passwords are enabled by default. This means is that all passwords in
  237: `/etc/passwd` are set to `\*`; the encrypted passwords are stored in a file that
  238: can only be read by root: `/etc/master.passwd`. When you start
  239: [vipw(8)](http://netbsd.gw.com/cgi-bin/man-cgi?vipw+8+NetBSD-5.0.1+i386) to edit
  240: the password file, the program opens a copy of `/etc/master.passwd`; when you
  241: exit, vipw checks the validity of the copy, creates a new `/etc/passwd` and
  242: installs the new `/etc/master.passwd` file. Finally, vipw launches
  243: [pwd\_mkdb(8)](http://netbsd.gw.com/cgi-bin/man-cgi?pwd_mkdb+8+NetBSD-5.0.1+i386),
  244: which creates the files `/etc/pwd.db` and `/etc/spwd.db`, two databases which
  245: are equivalent to `/etc/passwd` and `/etc/master.passwd` but faster to process.
  246: 
  247: It is very important to *always* use `vipw` and the other tools for account
  248: administration
  249: ([chfn(1)](http://netbsd.gw.com/cgi-bin/man-cgi?chfn+1+NetBSD-5.0.1+i386),
  250: [chsh(1)](http://netbsd.gw.com/cgi-bin/man-cgi?chsh+1+NetBSD-5.0.1+i386),
  251: [chpass(1)](http://netbsd.gw.com/cgi-bin/man-cgi?chpass+1+NetBSD-5.0.1+i386),
  252: [passwd(1)](http://netbsd.gw.com/cgi-bin/man-cgi?passwd+1+NetBSD-5.0.1+i386))
  253: and to *never* directly modify `/etc/master.passwd` or `/etc/passwd`.
  254: 
  255: ## Changing the keyboard layout
  256: 
  257: If you do not have a US layout keyboard, you probably want to change keymaps.
  258: For example, to use an italian keyboard, enter the following command:
  259: 
  260:     # wsconsctl -k -w encoding=it
  261:     encoding -> it
  262: 
  263: To save the keyboard layout permanently, add the following line to the
  264: `/etc/wscons.conf` file:
  265: 
  266:     encoding it
  267: 
  268: See [[Keyboard mappings|guide/cons#keyboard_mappings]] for a list of
  269: available keymaps.
  270: 
  271: ## System time
  272: 
  273: NetBSD, like all Unix systems, uses a system clock based on Greenwich time (GMT)
  274: and this is what you should set your system clock to. If you want to keep the
  275: system clock set to the local time (because, for example, you have a dual boot
  276: system with Windows installed), you must notify NetBSD by adding
  277: `rtclocaltime=YES` to `/etc/rc.conf`:
  278: 
  279:     # echo rtclocaltime=YES >> /etc/rc.conf
  280:     # sh /etc/rc.d/rtclocaltime restart
  281: 
  282: The number of minutes west of GMT is calculated automatically and is set in the
  283: `kern.rtc_offset` sysctl variable.
  284: 
  285: To display the current setting of the `kern.rtc_offset` variable:
  286: 
  287:     # sysctl kern.rtc_offset
  288:     kern.rtc_offset = -60
  289: 
  290: This automatic configuration only works if you have set the proper time zone by
  291: a symbolic link `/etc/localtime`. Normally this is done as part of the install
  292: procedure, but if for some reason it wasn't, you can set it by creating a
  293: symbolic link from `/etc/localtime` to a file in the `/usr/share/zoneinfo`
  294: directory.
  295: 
  296: The following example sets the time zone to Eastern Europe Summer Time:
  297: 
  298:     # ln -fs /usr/share/zoneinfo/Europe/Helsinki /etc/localtime
  299: 
  300: ## Secure Shell ([ssh(1)](http://netbsd.gw.com/cgi-bin/man-cgi?ssh+1+NetBSD-5.0.1+i386))
  301: 
  302: By default, all services are disabled in a fresh NetBSD installation, and
  303: [ssh(1)](http://netbsd.gw.com/cgi-bin/man-cgi?ssh+1+NetBSD-5.0.1+i386) is no
  304: exception. You may wish to enable it so you can log in to your system remotely.
  305: Set `sshd=YES` in `/etc/rc.conf` and then start the server with the command
  306: 
  307:     # /etc/rc.d/sshd start
  308: 
  309: The first time the server is started, it will generate a new keypair, which will
  310: be stored inside the directory `/etc/ssh`.
  311: 
  312: Note that you can enable sshd also by using the configuration menu of `sysinst`.
  313: If you did this, you don't have to do it by hand (and sshd should already have
  314: started at boot time).
  315: 
  316: ## Basic configuration in `/etc/rc.conf`
  317: 
  318: NetBSD uses `/etc/rc.conf` to determine what will be executed when the system
  319: boots. Understanding this file is important. The
  320: [rc.conf(5)](http://netbsd.gw.com/cgi-bin/man-cgi?rc.conf+5+NetBSD-5.0.1+i386)
  321: manual page contains a detailed description of all available options.
  322: 
  323: The `/etc/defaults/rc.conf` file contains the default values for most settings.
  324: To override a default value, the new value must be put into `/etc/rc.conf`. The
  325: definitions there override the ones in `/etc/defaults/rc.conf` (which you should
  326: leave unchanged).
  327: 
  328:     # man rc.conf
  329: 
  330: The first modifications are:
  331: 
  332:  * Set `rc_configured=YES` (this modification should already have been done by
  333:    the installation software.)
  334:  * Set `dhclient=YES` to configure your system's network using DHCP.
  335:  * Define a `hostname` for your machine (use a fully qualified hostname, i.e.,
  336:    one including domain). If you have a standalone machine you can use any name
  337:    (for example, `vigor3.your.domain`). If your machine is connected to a
  338:    network, you should supply the correct name.
  339:  * If your are connected to a local network or the Internet through a router,
  340:    set the `defaultroute` variable to the IP address of your router (sometimes
  341:    called a `default gateway`). For example, `defaultroute=192.168.1.1`.
  342: 
  343: ## Basic network settings
  344: 
  345: To resolve the names and IP addresses of remote hosts, the system needs access
  346: to a (remote or local) *DNS nameserver*. Tell the system which nameserver(s) to
  347: use by adding the IP address of one or more nameservers to the
  348: `/etc/resolv.conf` file, using the following as an example:
  349: 
  350:     nameserver 145.253.2.75
  351: 
  352: There are public name servers available, but your Internet Service Provider
  353: should always provide some to you anyway.
  354: 
  355: To set the names of local hosts that are not available through DNS, edit the
  356: `/etc/hosts` file, which has the form:
  357: 
  358:     IP-address  hostname  host
  359: 
  360: For example:
  361: 
  362:     192.168.1.3 vigor3.your.domain vigor3
  363: 
  364: ## Mounting a CD-ROM
  365: 
  366: New users are often surprised by the fact that although the installation program
  367: recognized and mounted their CD-ROM perfectly, the installed system seems to
  368: have "forgotten" how to use the CD-ROM. There is no special magic for using a
  369: CD-ROM; you can mount it like any other file system. All you need to know is the
  370: device name and some options to the
  371: [mount(8)](http://netbsd.gw.com/cgi-bin/man-cgi?mount+8+NetBSD-5.0.1+i386)
  372: command. You can find the device name with the aforementioned
  373: [dmesg(8)](http://netbsd.gw.com/cgi-bin/man-cgi?dmesg+8+NetBSD-5.0.1+i386)
  374: command. For example, if dmesg displays:
  375: 
  376:     # dmesg | grep ^cd
  377:     cd0 at atapibus0 drive 1: <ASUS CD-S400/A, , V2.1H> type 5 cdrom removable
  378: 
  379: the device name is `cd0`, and you can mount the CD-ROM with the following
  380: commands:
  381: 
  382:     # mkdir /cdrom
  383:     # mount -t cd9660 -o ro /dev/cd0a /cdrom
  384: 
  385: To make things easier, you can add a line to the `/etc/fstab` file:
  386: 
  387:     /dev/cd0a /cdrom cd9660 ro,noauto 0 0
  388: 
  389: Without the need to reboot, you can now mount the CD-ROM with:
  390: 
  391:     # mount /cdrom
  392: 
  393: When the CD-ROM is mounted you can't eject it manually; you will have to unmount
  394: it before you can do that:
  395: 
  396:     # umount /cdrom
  397: 
  398: There is also a software command which unmounts the CD-ROM and ejects it:
  399: 
  400:     # eject /dev/cd0a
  401: 
  402: ## Mounting a floppy
  403: 
  404: To mount a floppy you must know the name of the floppy device and the file
  405: system type of the floppy. Read the
  406: [fdc(4)](http://netbsd.gw.com/cgi-bin/man-cgi?fdc+4+NetBSD-5.0.1+i386) manpage
  407: for more information about device naming, as this will differ depending on the
  408: exact size and kind of your floppy disk. For example, to read and write a
  409: floppy in MS-DOS format you use the following command:
  410: 
  411:     # mount -t msdos /dev/fd0a /mnt
  412: 
  413: Instead of `/mnt`, you can use another directory of your choice; you could, for
  414: example, create a `/floppy` directory like you did for the CD-ROM. If you do a
  415: lot of work with MS-DOS floppies, you will want to install the
  416: [sysutils/mtools](http://pkgsrc.se/sysutils/mtools) package, which enables you
  417: to access a MS-DOS floppy (or hard disk partition) without the need to mount it.
  418: It is very handy for quickly copying a file to or from a floppy:
  419: 
  420:     # mcopy foo bar a:
  421:     # mcopy a:baz.txt baz
  422:     # mcopy a:\*.jpg .
  423: 
  424: ## Installing additional software
  425: 
  426: ### Using packages from pkgsrc
  427: 
  428: If you wish to install any of the software freely available for UNIX-like
  429: systems you are strongly advised to first check the NetBSD package system,
  430: [pkgsrc](http://www.pkgsrc.org). pkgsrc automatically handles any changes
  431: necessary to make the software run on NetBSD. This includes the retrieval and
  432: installation of any other packages on which the software may depend.
  433: 
  434: pkgsrc might have been installed already by `sysinst`, so you don't have to
  435: install it manually.
  436: 
  437:  * See the [list of available
  438:    packages](http://ftp.NetBSD.org/pub/NetBSD/packages/pkgsrc/README-all.html)
  439: 
  440:  * Precompiled binaries are available on the NetBSD FTP server for some ports.
  441:    To install them the `PKG_PATH` variable needs to be adjusted in the following
  442:    way (under the
  443:    [sh(1)](http://netbsd.gw.com/cgi-bin/man-cgi?sh+1+NetBSD-5.0.1+i386) shell):
  444: 
  445:        # export PKG_PATH="http://ftp.NetBSD.org/pub/pkgsrc/packages/NetBSD/<PORT>/<RELEASE-NUMBER>/All"
  446:        # export PKG_PATH
  447: 
  448:    Where `<RELEASE-NUMBER>` needs to be replaced by the release number of an
  449:    existing NetBSD release (for example, 6.1). `<PORT>` needs to be replaced by
  450:    the Port name for the used architecture (for example, amd64)
  451: 
  452:    Applications can now be installed by `root` with the pkg\_add command:
  453: 
  454:        # pkg_add -v perl
  455:        # pkg_add -v apache
  456:        # pkg_add -v firefox
  457:        # pkg_add -v kde
  458: 
  459:    The above commands will install the Perl programming language, Apache web
  460:    server, Firefox web browser and the KDE desktop environment as well as all
  461:    the packages they depend on.
  462: 
  463:    Installed applications can be updated in the following way:
  464: 
  465:        # pkg_add -uv firefox
  466: 
  467:    The following command will force an update of firefox and all of its
  468:    dependencies:
  469: 
  470:        # pkg_add -fuuv firefox
  471: 
  472:    All details about package management can be found in [*The pkgsrc
  473:    guide*](http://www.NetBSD.org/docs/pkgsrc/index.html)
  474: 
  475:  * Maybe you already installed
  476:    [pkgtools/pkgin](http://pkgsrc.se/pkgtools/pkgin). `sysinst` provides an
  477:    option to install pkgin (if not, you can install it like any other software).
  478:    `pkgin` is a binary package manager, but more sophisticated than `pkg_add`.
  479:    It maintains a database of packages on the server you can fetch with:
  480: 
  481:        # pkgin update
  482: 
  483:    Its usage is oriented on the package tools you have with other operating
  484:    systems. To search the package database for a word `stat`, use
  485:    
  486:        # pkgin search WORD
  487: 
  488:    To install a package (in this case `fscd`), just type
  489: 
  490:        # pkgin install fscd
  491: 
  492:    You should read the manpage to know about more actions you can do with pkgin.
  493: 
  494: ### Storing third-party software
  495: 
  496: On many UNIX-like systems the directory structure under `/usr/local` is reserved
  497: for applications and files which are independent of the system's software
  498: management. This convention is the reason why most software developers expect
  499: their software to be installed under `/usr/local`. NetBSD has no `/usr/local`
  500: directory, but it can be created manually if needed. NetBSD does not care about
  501: anything installed under `/usr/local`, so this task is left to you as the system
  502: administrator.
  503: 
  504: ### Security alerts
  505: 
  506: ## Security alerts
  507: 
  508: By the time that you have installed your system, it is quite likely that bugs in
  509: the release have been found. All significant and easily fixed problems will be
  510: reported at
  511: [http://www.NetBSD.org/support/security/](http://www.NetBSD.org/support/security/).
  512: It is recommended that you check this page regularly.
  513: 
  514: ## Stopping and rebooting the system
  515: 
  516: Use one of the following two shutdown commands to halt or reboot the system:
  517: 
  518:     # shutdown -h now
  519:     # shutdown -r now
  520: 
  521: Two other commands to perform the same tasks are:
  522: 
  523:     # halt
  524:     # reboot
  525: 
  526: halt, reboot and shutdown are not synonyms: the latter is more sophisticated. On
  527: a multiuser system you should really use shutdown, which allows you to schedule
  528: a shutdown time and notify users. It will also take care to stop processes
  529: properly. For more information, see the
  530: [shutdown(8)](http://netbsd.gw.com/cgi-bin/man-cgi?shutdown+8+NetBSD-5.0.1+i386),
  531: [halt(8)](http://netbsd.gw.com/cgi-bin/man-cgi?halt+8+NetBSD-5.0.1+i386) and
  532: [reboot(8)](http://netbsd.gw.com/cgi-bin/man-cgi?reboot+8+NetBSD-5.0.1+i386)
  533: manpages.
  534: 

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