How do I clone a 4Gb SDHC Card to another 4Gb SDHC Card
 

I have 2 identical SanDisk Ultra SDHC Cards, 4Gb.
I have been using one SDHC card to boot a notebook and run Xubuntu off it.
Works great.
It contains the boot, root and a little swap space.

The second SDHC is a brand new unused card.

When I insert these into my Ubuntu desktop, they show up as:
/dev/sda
/dev/sdb

I want to make an *EXACT* copy of the first SDHC card onto the second SDHC card.

What should I type on the Ubuntu command line to do this type of cloning?

Job done

Dave

Thanks Dave.
That did it.

Having a swap partition on an SD card is not a good idea. Also, you want to add the "noatime" mount option for the partitions. An SD card has a limited number of writes. If you use "noatime", the access times aren't recorded on the filesystem for every read. A swap partition may be written to at a high frequency. This could wear out the card prematurely.