How to check 64bit or 32bit CPU ?

Lately I stumbled upon this post on the web:

Hi All,

Any one knows the utility, which will provide info about the
CPU used in the machine is 32 bit or 64 bit ?

Thanks

I was wondering about this myself from time to time…
The good news is – in Linux you can figure that out in no
time by typing:

cat /proc/cpuinfo

If you can find the “lm” flag (lm for long mode) in the flag section, it’s a
64-bit machine. If not it’s most likely a 32-bit box you are dealing with.

Rescan the SCSI bus under Linux

Sometimes you want to rescan the SCSI bus, when e.g. adding a new virtual disc in a virtual machine…

Here you can find a very nice shell script, which accomplishes the job:

http://blog.sun.com/roller/resources/le/rescan-scsi-bus.sh

On debian based distributions you can find it in the scsitools package.

How to mount your ro system disk as rw again?

Sometimes your Linux boots with your system disk mounted readonly (because of some fs issues for instance).
So if you want to change stuff e.g. in /etc/fstab this becomes quite unhandy.

To get e.g. “/” writeable again, you just remount it with this one-liner:

mount -o remount,rw /

Good luck.
(This is also one of those tings, I can never remember…)