topic Re: can not boot in single mode in Operating System - Linux

can not boot in single mode

Anh-Thu Tran — Tue, 01 Nov 2005 10:51:04 GMT

Hi,
I am in the dead end now. During the Linux installation, somehow it did not ask me for the root passwd. Now the installation is done, but I don't know what the root passwd is. I tried to boot to single mode to re-install again, but failed. I tried from the GRUB boot loader, but it did not take anything a or e or space bar even how quickly I am, the machine just booted normally. What should I do?

Re: can not boot in single mode

Alexander Chuzhoy — Tue, 01 Nov 2005 10:56:49 GMT

boot from the first installation cd and type linux rescue
at the prompt
when the system will boot into rescue environment edit the file /mnt/sysimage/etc/inittab locate the line

1:2345:respawn:/sbin/mingetty tty1
and change it to
1:2345:respawn:/sbin/mingetty tty1 --autologin root
(all on the same line)
save and exit and boot your system normally.
This will cause root to login automatically on first terminal -tty1.
when you're logged in as root-do all necessary changes....

Re: can not boot in single mode

Anh-Thu Tran — Tue, 01 Nov 2005 11:02:34 GMT

How can I boot from the first cd installation? I could not get the prompt.

Re: can not boot in single mode

Alexander Chuzhoy — Tue, 01 Nov 2005 11:13:59 GMT

Configure your bios to try to boot from cd before trying from hard disk, place the first installation cd in the cdrom and boot the pc.
As installation option type
linux rescue

Re: can not boot in single mode

Anh-Thu Tran — Tue, 01 Nov 2005 14:52:55 GMT

Could you please tell me more details how to configure to boot from cdrom, instead of hdisk? I believe that I should change the bootlist, but not sure I can do it without root id.

Re: can not boot in single mode

Alexander Chuzhoy — Wed, 02 Nov 2005 01:22:23 GMT

You should enter to bios configuration.
On most computers you do it with: del or F2
button upon boot.

Re: can not boot in single mode

Anh-Thu Tran — Wed, 02 Nov 2005 16:22:06 GMT

F2 does work for me. Now I am able to boot from cdrom. Thank you very much.

Re: can not boot in single mode

Anh-Thu Tran — Fri, 04 Nov 2005 10:03:37 GMT

Now I can boot from cdrom and got the promt boot: . However, I could not type anything (I wanted to type linux rescue) even I could not type "linux text" as one of its options. I also saw the option F5-rescue, but nothing happened when I press F5. The promt just sat there a while and started the installation from cdrom that I don't want because I don't need the installation. What should I do? Thanks in advance.

Re: can not boot in single mode

Ivan Ferreira — Fri, 04 Nov 2005 10:11:26 GMT

That's weird, it seems that your keyboard is not working when booting from the installation CD, maybe an IRQ conflict?

Did you changed anything else in the setup program? You may try settings BIOS values to default, and then configure the boot options again to start with cdrom first.

Re: can not boot in single mode

Anh-Thu Tran — Fri, 04 Nov 2005 10:24:31 GMT

Does I need to take the CD out after getting the boot promt or still leave it inside?

Re: can not boot in single mode

Ivan Ferreira — Fri, 04 Nov 2005 13:56:54 GMT

You should leave it inside.

Re: can not boot in single mode

Ralph Grothe — Sat, 05 Nov 2005 20:40:54 GMT

As Alexander already pointed out,
you seem to have a problem with your keyboard
if you cannot type anything at the boot prompt even when booted from a bootable CD.
It is quite common with these PS2 plugs that a pin accidentily gets bent and squeezed.
Check your cabling.

Besides, you don't necessarily need a bootable CD (e.g. installation 1) to get into single user mode.

When the Grub screen appears move with the arrow keys to the boot entry for the kernel you usually auto boot.
When on the line with the vmlinuz* type e to edit the line.
Move to the end of the line and append a space separated s (like single user mode) as kernel argument, and after Esc type b (like boot)
This should bring you to single user mode.
(Note that you have a US keymapping while in Grub, e.g. I always have to type z for y and vice versa because I have a qwertz keyboard)

Also you could append as kernel argument
init=/bin/sh
which should give you a root shell instead of init.
But you have to fsck and remount / rw before you can edit /etc/shadow.

If you don't get the Grub menu displayed it could be that hiddenmenu is set in your grub.conf file.
Just type c to get into Grub command mode.
There help would present you online help of grub commands.
Grub can search for any kernels on your boot devices and has many neat features.
It even can boot via network (if the prerequisites are met).
Read info grub for details.