Execute a command before shutdown

I don't know what i did or what happened?

but my ubuntu logs off on clicking shutdown...

running the shutdown or reboot command too doesn't shutdown....

how can i find the log?

all i know is there is a message saying ....

Power_table_CMD wait for 500 sec

and something similar

it gets stuck on Ubuntu Plymouth...

I have to long press the power button on my Laptop to shut it off

I have googled for a while, but I still haven't found a clear answer to the differences between halt and poweroff options for shutdown. So I would like to ask this question here.

If it helps, my computer is Lenovo T400 and OS is Ubuntu 12.04

Note: I am talking about two options to the command shutdown.

I have ubuntu 11.10 64bit, everything worked fine but after i uninstalled the airtime dj app i can't restart or shutdown my pc !! The only way to reach at the screen showing that system is going to shutdown is via terminal but it stucks and never shuts down ! I can't even restart it ! I can suspend my pc fine but can't shutdown or restart it.

Using Remote Desktop (RDP/Terminal Services), I can't select Shutdown/Reboot from the Windows XP start menu, so I generally have to open a terminal and enter shutdown -s -t 0 to initiate an immediate shutdown.

But, for a new system, I have added a non-administrative user to the Remote Desktop Users group, and when I try to issue a shutdown command as that user, the command returns the following e

When I try to shutdown or reboot from the system menu in Fedora 12, I am returned to the logon prompt. I am able to shutdown and reboot from a terminal window by issuing the shutdown command as the root user.:(

Any ideas?

Thanks for your help.

DoubleG

As the title says: when I click Shutdown from the menu it logs off. When I click shutdown from the log-in menu it does nothing. I'm using a fresh install of Ubuntu 11.10. I can force it to shutdown by the command below, but I don't want to keep typing that whenever I want to shutdown my laptop.

sudo shutdown -h now

So it's probably processes which arn't closing.

With 11.2 and Gnome occasionally it will not shutdown properly. I press the shutdown button and then Gnome starts the shutdown sequence. It terminates the desktop and falls back to GDM, which in it self is normal. However it then just stops, I can't click anything and the system is not responding either. When I press the physical button on my PC I get the menu of shutdown again.

Is there a way to "gracefully" shutdown tomcat when controlling via supervisor?

My understanding is Tomcat's shutdown.sh script talks to tomcat on the shutdown port to initiate a graceful shutdown.

I wrote a script that suspend all my virtualbox machines, and put a line in /etc/rc.local.shutdown, but it doesn't seem to work,

su - XX -c /XX

When I'm booted next time, virtualbox tells me the machine was Aborted, so the script wasn't executed. (Launching that script manually works for me)

P.S I already enabled shutdown.target