How to download a linux image, unzip it and write it to an SD card in one line?

Question

I am operating a Linux live image on a small USB flash drive and would like to flash an SD card with it. The image is zipped already too big for my flash drive, so I can not write it to disk. I have enough RAM to buffer the zipped and the unzipped image, so my solution was this:

$ sudo mount -t tmpfs -o size=2.5G none /mnt 
$ cd /mnt && wget http://example.com/linux.zip
$ cd /mnt && unzip linux.zip
$ sudo dd if=/mnt/linux.img of=/dev/sdb bs=4M

This feels cumbersome. How one write an image to SD card, unzipped from an archive, downloaded from the internet, without writing anything to disk in one line?

Answer 1

If your live image comes with curl, funzip and dd, something like the following should work:

$ curl -L http://example.com/linux.zip | funzip | dd of=/dev/sdb bs=4M

Answer 2

Try with this: wget http://example.com/linux.zip -q -O -| funzip | dd of=/dev/sdb bs=4M