$ ll /etc/network/if-pre-up.d/
total 20
drwxr-xr-x 2 root root 4096 Jan 15 16:43 ./
drwxr-xr-x 7 root root 4096 Jan 14 21:29 ../
-rwxr-xr-x 1 root root 344 Apr 28 2012 ethtool*
-rwxr-xr-x 1 root root 158 Jan 14 22:01 iptablesload.sh*
-rwxr-xr-x 1 root root 3839 May 3 2012 wireless-tools*
lrwxrwxrwx 1 root root 32 Dec 4 13:00 wpasupplicant -> ../../wpa_supplicant/ifupdown.sh*
$ sudo ifup --all -v
run-parts --verbose /etc/network/if-pre-up.d
run-parts: executing /etc/network/if-pre-up.d/ethtool
run-parts: executing /etc/network/if-pre-up.d/wireless-tools
run-parts: executing /etc/network/if-pre-up.d/wpasupplicant
run-parts --verbose …networking ×1