Normally when you list the files in your directory/sub-directory with the ls command you would get the paths to those files with respect to the current directory.
But what if you wanted to save this list and you wanted the absolute paths rather than the relative paths. Well it doesn’t strike you first but then when you know it, its like, “Oh its that obvious!”
So you do
ls -d $PWD/what_ever_you_are_trying_to_list
The $PWD gets filled with the path to the current directory.
might have yielded
ls -d $PWD/work/*.md
would yield something like