How to make SD card copy under Ubuntu ?

skywalker

Hello all,

I am newbee on those nice orange pi card as well as with linux system ( run windows for long time and do some prog too under Win and Android...)
I install the ubuntu vivid mate then Apache + PHP + MySql + PhpMyAdmin and all my files on www.
Now I just finished one SD card that boot and run very well on both card I got (Orange PI 2 and Orange PI 2 mini)

I would like now duplicate this "Master" SD card for the other OPI and also get a safe copy in case of crash.

I try to duplicate and create image with win32 imager but I use a 64 GO sd card for this first install and this take day to get back the image in this way
and I would like also  now to reduce the SD to maybe only 8GO.

I saw there was command to write this in EMMC and then get it back but unforntunately  there is no memory on those board, need plus version :-(

As I have a SD to USB adapter so can boot on the original and then copy to SD/USB

Can someone give me complete procedure to achive this backup/ restore  ?

Sky