The question is simply this: how is the PAGER variable set by default for all users in Ubuntu Linux? Where is this done (in terms of a standard file or location)?
A secondary question is how might this get unset?
I have been told to use /etc/profile and/or /etc/environment to fix it, and I am experimenting with these as solutions, but neither of these was used to set the PAGER variable originally. Where should this have been done?
Here is the problem that led me to this question:
man stopped working on my Ubuntu (18.04) system a while ago. I did not notice that it had failed at first until git log also failed and I saw this answer on fixing that. When I use the command export PAGER=more it fixes the problem with both man and git.
To fix the problem for me, I have added the line:
export PAGER=more
to my .bashrc file. It took some looking around to realize the difference between that command and just PAGER=more, but this answer spelled it out for me. I guess my calls to man and git are subprocesses, and adding the export in front is needed for them to have access to the variable. (If that is wrong, please inform me!)