How to start single user mode or safe mode
Jez Hancock
jez.hancock at munk.nu
Mon Feb 23 10:50:26 PST 2004
On Mon, Feb 23, 2004 at 10:49:53PM +0800, Stephen Liu wrote:
> Accidentally I made a mistake
>
> # ee /etc/rc.conf
> .....
> hostname=localhost
> ....
>
> and could not start the PC
>
> At booting
> ......
> Enter full pathname of shell or RETURN for /bin/sh:
> Hit <ENTER>
> # ee (could not work)
>
> I rebooted the PC. At booting, selecting [3] or [4] could not boot to
> 'safe mode' nor 'single user mode'
Firstly it would help if you could tell us why you were originally
dropped to single user mode - ie the messages prior to 'Enter full
pathname of shell...'.
To boot into single user mode at startup:
- hit any key APART FROM ENTER when the system counts down from 10.
This will take you to the boot prompt.
- type 'boot -s' to boot into single user mode
After booting into single user mode, to be able to write any changes
/etc to disk you need to change the status of the / partition from read
only to read/write mode. To do this execute:
/sbin/mount -u /
Note you should use the full path because /sbin may not be in your PATH
for one reason or another.
Now you can move on to fix any problems with /etc/rc.conf. If you
really want to use ee(1) then you'll need to first mount the partition
containing /usr/sbin since ee(1) resides there and if the partition
containing /usr/sbin isn't mounted you won't be able to use ee(1).
If /usr has it's own dedicated partition you'd do:
mount /usr
generally.
Finally you should be able to do:
/usr/sbin/ee /etc/rc.conf
again using the full path to ee(1).
This is one of the reasons I forced myself to learn ed(1)/vi(1) - it's the one
editor that's generally available no matter what when you boot a system
in single user mode.
--
Jez Hancock
- System Administrator / PHP Developer
http://munk.nu/
http://jez.hancock-family.com/ - Another FreeBSD Diary
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