Dear Maintainer,

*** Reporter, please consider answering these questions, where appropriate ***

   * What led up to the situation?
   Sometimes, when I have one interface up (say: eth0) I want to put up another interface (say: wlan0) and set default route to it.
   Sometimes I want to have defaultroute unchanged.

   * What exactly did you do (or not do) that was effective (or
     ineffective)?
   Cannot see appropriate option.

   * What was the outcome of this action?
   Default route is unchanged - has to be changed manually.

   * What outcome did you expect instead?

   when I do: "ifup wlan0 -o "replacedefaultroute=yes" - default route is set to new interface.

*** End of the template - remove these template lines ***
--- up and down scripts installed:
/etc/network/if-down.d:
total 24
-rwxr-xr-x 1 root root 1015 Jan 23  2017 avahi-autoipd
-rwxr-xr-x 1 root root  283 Feb 19  2015 bind9
-rwxr-xr-x 1 root root  289 Jan 16 00:12 bind9.dpkg-dist
-rwxr-xr-x 1 root root  283 Dec 10 20:23 bind9~
lrwxrwxrwx 1 root root   26 Apr  6  2014 debug -> /etc/network/if-up.d/debug
lrwxrwxrwx 1 root root   29 Apr  6  2014 iptables -> /etc/network/if-up.d/iptables
-rwxr-xr-x 1 root root  372 Mar 17  2014 openvpn
-rwxr-xr-x 1 root root  256 May  8  2013 resolvconf
lrwxrwxrwx 1 root root   32 Dec 28 11:26 wpasupplicant -> ../../wpa_supplicant/ifupdown.sh

/etc/network/if-post-down.d:
total 4
lrwxrwxrwx 1 root root   23 Sep 18 23:25 avahi-daemon -> ../if-up.d/avahi-daemon
lrwxrwxrwx 1 root root   29 Jun 26  2017 bridge -> /lib/bridge-utils/ifupdown.sh
lrwxrwxrwx 1 root root   26 Apr  6  2014 debug -> /etc/network/if-up.d/debug
lrwxrwxrwx 1 root root   29 Apr  6  2014 iptables -> /etc/network/if-up.d/iptables
-rwxr-xr-x 1 root root 1409 Mar 24  2016 wireless-tools
lrwxrwxrwx 1 root root   32 Dec 28 11:26 wpasupplicant -> ../../wpa_supplicant/ifupdown.sh

/etc/network/if-pre-up.d:
total 28
lrwxrwxrwx 1 root root   29 Jun 26  2017 bridge -> /lib/bridge-utils/ifupdown.sh
lrwxrwxrwx 1 root root   29 Jun 26  2017 bridge~ -> /lib/bridge-utils/ifupdown.sh
-rwxr-xr-x 1 root root  344 Jan 28  2014 ethtool
-rwxr-xr-x 1 root root  344 Jun 30  2016 ethtool~
-rwxr-xr-x 1 root root  137 Aug 16  2016 uml-utilities
-rwxr-xr-x 1 root root 4178 Mar 24  2016 wireless-tools
lrwxrwxrwx 1 root root   32 Dec 28 11:26 wpasupplicant -> ../../wpa_supplicant/ifupdown.sh
-rwx------ 1 root root  771 Oct 19  2014 wwan
-rwx------ 1 root root  771 Oct 19  2014 wwan~

/etc/network/if-up.d:
total 88
-rwxr-xr-x 1 root root  817 May  8  2013 000resolvconf
-rwxr-xr-x 1 root root  923 Jan 23  2017 avahi-autoipd
-rwxr-xr-x 1 root root  484 Nov 26  2013 avahi-daemon
-rwxr-xr-x 1 root root  484 Jan 23  2017 avahi-daemon~
-rwxr-xr-x 1 root root  484 Jan 23  2017 avahi-daemon~~
-rwxr-xr-x 1 root root  283 Feb 19  2015 bind9
-rwxr-xr-x 1 root root  289 Jan 16 00:12 bind9.dpkg-dist
-rwxr-xr-x 1 root root  283 Dec 10 20:23 bind9~
-rwxr-xr-x 1 root root   37 Apr  8  2014 debug
-rwxr-xr-x 1 root root   37 Apr  8  2014 debug~
-rwxr-xr-x 1 root root 1685 Sep 22  2014 ethtool
-rwxr-xr-x 1 root root 1685 Jun 30  2016 ethtool~
-rwxr-xr-x 1 root root  795 Jan 22 15:35 iptables
-rwxr-xr-x 1 root root 4958 Jun  8  2014 mountnfs
-rwxr-xr-x 1 root root 4958 Feb 12  2017 mountnfs~
-rwxr-xr-x 1 root root  900 Apr 28  2016 ntpdate
-rwxr-xr-x 1 root root  972 Jun 18  2017 openssh-server
-rwxr-xr-x 1 root root  972 Oct 17 10:56 openssh-server~
-rwxr-xr-x 1 root root  385 Jul  7  2015 openvpn
-rwxr-xr-x 1 root root  261 Nov 14  2014 uml-utilities
lrwxrwxrwx 1 root root   32 Dec 28 11:26 wpasupplicant -> ../../wpa_supplicant/ifupdown.sh