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发表于 2006-11-17 10:37:11
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Runlevel
A runlevel is a mode of operation that is used to group certain sets of daemons based on some purpose or restricted use. For the Fedora/Redhat based Linux systems, the primary runlevels in Fedora are:
• runlevel 1: Single-User Mode
• runlevel 2: Multi-User Mode
• runlevel 3: Multi-User Mode with Networking
• runlevel 5: X11 (runlevel 3 + X Window System "the GUI").
Typically most users run with the X-server in runlevel 5, and many servers without X-servers run in runlevel 3. Usually runlevel 1 has no services running.
To determine what runlevel you are using, run:
# /sbin/runlevel
To determing what runlevel your system will start at the next boot, run:
# cat /etc/inittab | grep :initdefault:
id:5:initdefault:
Similarily you can edit the file /etc/inittab and change the initdefault value at line ~18.
To switch runlevels, you can run the following, replace RUNLEVEL with the appropriate number (3, 5, etc.):
# /sbin/init RUNLEVEL
Note: When switching FROM runlevel 5 to another runlevel, you might accidentally kill your X-server and entire GUI. Always make sure you are at a text console (CTRL-ALT-F1,F2,F3,F4) before switching runlevels.
To force a runlevel at boot without modifying /etc/inittab, you pass a number to end of the kernel from the Grub menu. At boot, higlight the option you wish to boot and before hitting <Enter>, hit <E>. Go to the end of the kernel line and add a 3 or 5. Then hit <Enter> and boot (<B> to boot). |
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