Diff for /wikisrc/guide/rc.mdwn between versions 1.1 and 1.7

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 # The rc.d System  This page was moved to:
   [The NetBSD Guide - The rc.d System](//www.NetBSD.org/docs/guide/en/chap-rc.html)
 NetBSD uses individual scripts for controlling system and service startup,   
 similar to System V, but without runlevels.  
 Nowadays, most Linux distributions switched to systemd, which is a different   
 approach: It does not use scripts anymore, but tries to have everything binary.   
 It also serves for several other purposes, while NetBSD's rc.d system just   
 serves for starting up services at system startup or by user intervention.  
 This chapter is an overview of NetBSD's rc.d system and its configuration.  
 ## Basics  
 The system startup files reside in the `/etc` directory. They are:  
  * `/etc/rc`  
  * `/etc/rc.conf`  
  * `/etc/rc.d/*`  
  * `/etc/rc.lkm`  
  * `/etc/rc.local`  
  * `/etc/rc.shutdown`  
  * `/etc/rc.subr`  
  * `/etc/defaults/*`  
  * `/etc/rc.conf.d/*`  
 First, a look at controlling and supporting scripts (also documented in   
  * After the kernel has initialized all devices at startup, it starts   
    which in turn runs `/etc/rc`.  
  * `/etc/rc` sorts the scripts in `/etc/rc.d` using   
    and then runs them in that order. See below and the manpage for details of  
    how the order of rc.d scripts is determined.  
  * `/etc/rc.subr` contains common functions used by `/etc/rc` and various rc.d   
  * When shutting down the system with   
    `/etc/rc.shutdown` is run, which runs the scripts in `/etc/rc.d` in  
    reverse order (as defined by   
    *Note*: If you shut down the system using the   
    command, these scripts will not be run.  
 There are some special scripts outside the `rc.d` directory, which are also  
  * `/etc/rc.lkm` loads or unloads Loadable Kernel Modules (LKMs). See   
    and `/etc/rc.d/lkm[123]`.  
  * `/etc/rc.local` is almost the last script called at boot up. This script can   
    be edited by the administrator to start local daemons that don't fit the  
    rc.d model, or do maintenance that should be done only once at startup.  
 rc.d scripts are controlled by a central configuration file, `/etc/rc.conf`,   
 which loads its default settings from `/etc/defaults/rc.conf`. If you want to   
 change a default setting, do not edit `/etc/defaults/rc.conf`; instead, override   
 the setting in `/etc/rc.conf`.  
 It is a good idea to read the   
 man page to learn about the services that are by default available to you.  
 The following example shows how to enable the SSH daemon, which is disabled by   
     # cd /etc; grep ssh defaults/rc.conf  
     sshd=NO                 sshd_flags=""  
     # echo "sshd=YES" >> rc.conf  
 Now [sshd(8)](http://netbsd.gw.com/cgi-bin/man-cgi?sshd+8+NetBSD-5.0.1+i386)   
 will be started automatically at system startup. The next section describes how   
 to start and stop services at any time.  
 Last but not least, files can be created in the `/etc/rc.conf.d/` directory to   
 override the behavior of a given rc.d script without editing the script itself.  
 ## The rc.d scripts  
 The actual scripts that control services are in `/etc/rc.d`. These scripts are   
 automatically run at boot time, but they can be called manually if necessary.   
 The following example shows how to start the SSH daemon that we enabled in the   
 previous section:  
     # /etc/rc.d/sshd start  
     Starting sshd.  
 Later, if you wish to stop the SSH daemon, run the following command:  
     # /etc/rc.d/sshd stop  
     Stopping sshd.  
     Waiting for PIDS: 123.  
 The rc.d scripts take one of the following arguments:  
  * `start`  
  * `stop`  
  * `restart`  
  * `status`  
 Some scripts may support other arguments (e.g., `reload`), but every script will   
 support at least the above commands.  
 As an example, after adding a new record to a   
 database, the daemon can be told to reload its configuration files with the   
 following command:  
     # /etc/rc.d/named reload  
     Reloading named config files.  
 Note that all of the commands discussed above will only take action if the   
 particular service is enabled in `/etc/rc.conf`. It is possible to bypass this   
 requirement by prepending `one` to the command, as in:  
     # /etc/rc.d/httpd start  
     $httpd is not enabled - see rc.conf(5).  
     Use the following if you wish to perform the operation:  
       /etc/rc.d/httpd onestart  
     # /etc/rc.d/httpd onestart  
     Starting httpd.  
 The above command will allow you to start the   
 service one time. To stop a service that has been started in this manner, pass   
 `onestop` to the script.  
 ## Order/dependencies of start determined by rcorder  
 The startup system of every Unix system determines, in one way or another, the   
 order in which services are started. On some Unix systems this is done by   
 numbering the files and/or putting them in separate run level directories.   
 Solaris relies on wildcards like `/etc/rc[23].d/S*` being sorted numerically   
 when expanded. Some simply put all the commands that should be started into a   
 single monolithic script (this is the traditional BSD method, and is what NetBSD   
 did before the rc.d system). On modern NetBSD this is done by the rc.d scripts   
 and their contents. Please note that NetBSD does not have multiple runlevels as   
 found in SysV-style systems like Solaris and Linux.  
 At the beginning of each rc.d script there is a series of commented out lines   
 that have one of the following items in them:  
  * `REQUIRE`  
  * `PROVIDE`  
  * `BEFORE`  
  * `KEYWORD`  
 These describe the dependencies of that particular script and allow rcorder to   
 easily work either `up` or `down` as the situation requires. As an example, here   
 is the ordering information contained in `/etc/rc.d/nfsd`:  
      PROVIDE: nfsd  
      REQUIRE: rpcbind mountd  
 Here we can see that this script provides the `nfsd` service and that it   
 requires `rpcbind` and `mountd` to be running first. The   
 utility is used at system startup time to read through all the rc.d scripts and   
 determine the order in which they should be run.  
 ## rc.d scripts of additional services  
 Packages you install additionally won't be listed in the rc.conf(5) manpage.  
 Packages installing services which can be started with an rc.d script tell you  
 so after they are installed, along with the variable that is used for starting  
 them (usually, it has the same name as the service itself).  
 Then, you usually have to copy them from `/usr/pkg/share/examples/rc.d` to  
 `/etc/rc.d` for `rc` to automatically find them, or add the line  
     rc_directories="/etc/rc.d /usr/pkg/share/examples/rc.d"  
 to your `/etc/rc.conf`.  
 If you forgot the name of the service variable, you can have a look at the rc.d  
 script itself. The variable `rcvar` (usually set to `$name`) will tell you.  
 E.g., to find the name of variable to start fscd, run  
     $ grep ^rcvar /etc/rc.d/fscd  
         $ grep ^name /etc/rc.d/fscd   # Aaaw, no direct rcvar.  
 Thus, you need in your `/etc/rc.conf` the entry:  
 ## Additional Reading  
 Luke Mewburn, one of the principal designers of the rc.d system, gave a   
 presentation on the system at USENIX 2001. It is available in   
 [PDF](http://www.mewburn.net/luke/papers/rc.d.pdf) format.  

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