Introduction
As Jeremy Bicha wrote:
Posted on April 18, 2018 by Jeremy Bicha — 8 Comments
Today, gksu was removed from Ubuntu 18.04, four weeks after it was removed from Debian.
So theoretically speaking there are no packages on Bionic Beaver 18.04 LTS, depending on gksu. But this is not true:
$ apt-cache rdepends gksu
gksu
Reverse Depends:
gexec
wicd-gtk
spacefm-gtk3
spacefm
|menu
$ aptitude why gksu
i menu Suggests gksu | kde-runtime | ktsuss
As you see some software, which are distibuted by third-party may depend on gksu package. So you can proceed installing gksu with method below on your own risk.
How to fix?
Possible solution is to install version from previous (17.10, artful) release.
Warning: do not execute the commands below if unsure!
Short method (as @MK suggested)
wget http://archive.ubuntu.com/ubuntu/pool/main/libg/libgtop2/libgtop-2.0-10_2.32.0-1_amd64.deb
sudo apt install ./libgtop-2.0-10_2.32.0-1_amd64.deb
wget http://archive.ubuntu.com/ubuntu/pool/universe/libg/libgksu/libgksu2-0_2.0.13~pre1-6ubuntu8_amd64.deb
sudo apt install ./libgksu2-0_2.0.13~pre1-6ubuntu8_amd64.deb
wget http://archive.ubuntu.com/ubuntu/pool/universe/g/gksu/gksu_2.0.2-9ubuntu1_amd64.deb
sudo apt install ./gksu_2.0.2-9ubuntu1_amd64.deb
Test
Test gksu (should work on Xorg-sessions)
gksu-properties # check that it has "Authentication mode" to "sudo"
gksu date
gksudo date
Notes
After installation the following packages will be marked as obsolete (locally-installed): gksu, libgksu2-0. But they will work as expected.