Create qemu virtual image file:

qemu-img create virt1 1G

On my laptop for some reasons, no cdrom boot was allowed for the virtual installation,
so the loopback device comes useful to do the installation:

dd if=/dev/cdrom of=sarge-netinst.iso

Now boot the new OS installation (I use Debian GNU/Linux for both real and virtual systems)

qemu virt1 -boot d -cdrom sarge-netinst.iso


Then boot the new system (root or sudoed, as you need root privileges for routing)

qemu virt1 -boot c -n /etc/qemu-ifup


(from http://wiki.splitbrain.org/shellsnippets)


for i in 30 31 32 33 34 35 36 37 39
do
for j in 40 41 42 43 44 45 46 47 49
do
# skip if same fore- and backgroundcolor
if [ $j -eq $[ i + 10 ] ]; then
continue
fi
echo -e $i $j "\033[${i};${j}mCOLOR\033[0m"
done
done


Put the following little snippet in your .bashrc/.bash_profile and you'll have a handy little calculator:


? () { echo "$*" | bc -l; }


Use like this:

bash$ ? 2*2
4

Thanks textsnippets.com

from:

How to list duplicate lines in a text file, with counts next to each unique line - [spugbrap's random notes geek blog] [del.icio.us (bash)]

At some point, last year (it's been in my 'toblog' file all this time), I needed to analyze the lines in a text file, removing duplicate lines, while counting how many times each duplicated line occurred within the file, and sorting from most common to least common.

Generate an infinite loop in the shell

while true ; do date ; sleep 5 ; done