Linux - rc.d
All Linux distros use rc.d to handle initialization jobs. You can see files rc.0, rc.1, rc.2, rc.3, rc.4, rc.5, rc.6 in /etc, or directories rc0.d, rc1.d, rc2.d, rc3.d, rc4.d, rc5.d, rc6.d, which according to different distribution . Script files inside these sub-folders are the stuff Linux will do during logon. Number 0~6 correspond
runlevel 0~6. The default runlevel your PC will take is specified in file /etc/inittab as the line below:
id:4:initdefault:
You can specify jobs the specified runlevel will do respectively in the corresponding files(or directories). Note that for directories, actually files inside it usually are all symbolic links to /etc/init.d
There is a simple way to add your customized jobs: add them into file /etc/rc.local, which will be executed after all the other initialized works and before logon prompt.
id:4:initdefault:
You can specify jobs the specified runlevel will do respectively in the corresponding files(or directories). Note that for directories, actually files inside it usually are all symbolic links to /etc/init.d
There is a simple way to add your customized jobs: add them into file /etc/rc.local, which will be executed after all the other initialized works and before logon prompt.
| Run Level |
Generic |
Fedora Core |
Slackware |
Debian |
| 0 | Halt | Halt | Halt | Halt |
| 1 | Single-user mode | Single-user mode | Single-user mode | Single-user mode |
| 2 | Basic multi-user mode (without networking) | User definable (Unused) | User definable - configured the same as runlevel 3 | Multi-user mode |
| 3 | Full (text based) multi-user mode | Multi-user mode | Multi-user mode - default Slackware runlevel | |
| 4 | Not used | Not used | X11 with KDM/GDM/XDM (session managers) | Multi-user mode |
| 5 | Full (GUI based) multi-user mode | Full multi-user mode (with an X-based login screen) - default runlevel | User definable - configured the same as runlevel 3 | Multi-user mode |
| 6 | Reboot | Reboot | Reboot | Reboot |