Just a quick note: Today I had to create a CentOS bootable USB stick. I used to do that on a Linux box, but this time I had to use an OS X one. I checked a few posts online and dd seemed to be available on OS X, so I run something like:
time sudo dd if=CentOS-7-x86_64-Minimal-1503-01.iso of=/dev/disk2 bs=1m
I'm using a very old USB stick and the process was kind of slow. I decided to do the same I used to do on a Linux box and issued the following:
killall -USR1 dd
For my surprise, the dd process just finished suddenly :(
Searching on Google, I found some people saying that USR1 signal doesn't work on OS X, but none mentioned that it interrupts dd!
The proper way to do that on OS X is:
killall -INFO dd
EDIT:
After checking this link, I found out that Ctrl + T on the dd terminal window also do the same on OS X!
Hope it helps!