Debian xarchiver "Failed to execute child process "ar" (No such file or directory)"

Question

I have Debian 9 and Xfce. am trying to install a commercial program given as a .deb -ending file. When I double click on the file, it opens a window titled "(filename.deb) - Xarchiver 0.5.4" and on top of that a pop-up error message

Can't run the archiver executable:
Failed to execute child process "ar" (No such file or directory)

Is ar a command I'm missing? I tried on a terminal sudo apt-get install ar and the response is E: Unable to locate package ar

A similar problem seems to be in KDE opens .deb files with ar instead of a package manager but their context is KDE, not Xfce.

Answer 1

Installing ar won’t help; what you need to do is install the package you have. Since you mention using a terminal, use that:

cd /path/to/directory/containing/filename.deb
sudo apt install ./filename.deb

If you’d rather use a graphical tool, install gdebi first, then run that (from your launcher, or gdebi-gtk from the terminal); this is the Gtk variant of the gdebi-kde tool mentioned in KDE opens .deb files with ar instead of a package manager, and is appropriate for Xfce.