extract characters from a variable

Hi All,

I have scenario as below,
I want to cut the characters and store it variable2.. and want to display the variable2.. as shown below...

eg: the size may differs , i am show just an example.....

numbers are not fixed in variable1..i want to extract characters and display....

1) variable1 = 1.23kb
i need output: kb

2) variable1=1212121212323342424132GB
i need output : GB

3) variable1=1.3Mb
i need output:Mb

pls help me in solving this....

Thanks in advance...
k.k.

thanks to every one.... i resolved this issue ......