Error upgrading from Ubuntu 18.04 to 20.04

[Paul Smith]

On Thu, 2020-06-18 at 22:43 +0200, Tom H wrote:
> What do
> echo $PAGER

less -iR

> and
> ll /etc/alternatives/pager
> show?

-> /usr/bin/less

> Try
> PAGER="less" pager="less" apt-get -f install
> or
> PAGER="/usr/bin/less" pager="/usr/bin/less" apt-get -f install

To be clear, the pager worked fine before I started the upgrade (I
assume: certainly less worked; I use it 100's of times a day) and it
definitely worked fine after the (partial) upgrade (I tried it).  It
was only not found during the upgrade itself.  I also had another
package later in the upgrade that I used "d" to show diffs with, and
that time it worked.  So it wasn't even the entire upgrade that had
this problem, just near the beginning.