I recently thought about a devious trick that involves setting the PAGER
envionment variable to rev
as a joke.
When I tried reading the man page for rev with man rev
I then saw the man page in reverse as expected.
If you want to try this without setting your pager you can use the -P
option in man
like so: man -P rev rev
and you will see the man page for rev
in reverse.
The thing that confuses me is that you cannot simply pipe the output through rev to get it the right way around again. I tried running man -P rev rev | rev
and instead of getting the output the right way around, it is still reversed.
There is an error message displayed the correct way around, it looks like this:
mdoc warning: A .Bl directive has no matching .El (#58)
I presume this is in the correct direction because it came through stderr
and not stdout
If you simply pipe it through rev again, all of the text is in the correct direction, error message and all.
man -P rev rev | rev | rev
What is the reason for this odd behaviour?
I am using bash in gnome terminal on Ubuntu.