# read -p "Interface: " iface; ethtool -k $iface | awk -F: '/offload: on$/{print$1}' | sed 's/^\(.\).*-\(.\).*-\(.\).*/\1\2\3/' | xargs --no-run-if-empty -n1 -I{} ethtool -K $iface {} off


Disable offloading for all interfaces:

# for iface in $(cd /sys/class/net; echo *); do ethtool -k $iface | awk -F: '/offload: on$/{print$1}' | sed 's/^\(.\).*-\(.\).*-\(.\).*/\1\2\3/' | xargs --no-run-if-empty -n1 -I{} ethtool -K $iface {} off; done

A big thank you to Daniel C. for this!