I am using dd
to do a network transfer of a disk image to an sd card on my BeagleBone.
Using pkill -USR1 -n -x dd
in an ssh connection to this BeagleBone gives me a status update of the transfer process, which is great. I am just curious how it is actually working so I can use it effectively in the future.
After reading man pkill
it still didn't totally explain how pkill -USR1 -n -x dd
is working to give me this very useful status update.
Best Answer
This is behavior specific to
dd
. From thedd
man page:-USR1
tellspkill
to send theUSR1
signal.-n
and-x
are just filters to make sure you send to the right process (-n
sends to the newest process and-x
means the process must be named exactlydd
)