# apt install linux-headers-$(uname -r)
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package linux-headers-4.9.0-6-amd64
E: Couldn't find any package by glob 'linux-headers-4.9.0-6-amd64'
E: Couldn't find any package by regex 'linux-headers-4.9.0-6-amd64'
# lsb_release -a | grep Desc
No LSB modules are available.
Description: Debian GNU/Linux 9.4 (stretch)
You need to update kernel first before installing headers
You need to update kernel first before installing headers