WizenedEE:
Be a man! rm -r that thing! rm -rf it if you're hardcore.
Note to self: Next time I see WizenedEE say "Be a man!", take the wimpola option.
Seriously, using rm -rf with su privileges is not a matter of manliness, rather just to be sure you know what you are doing.
Breaking it down in case there is any doubt:
rm = remove (i.e., delete)
-r = recursively (i.e., the nominated directory and any subdirectories below it)
-f = force (ignore file attributes)
/ = the root of the file system is the nominated directory
sudo = make me su, I know what I'm doing
On systems like ubuntu at least, someone should probably put rm in a wrapper to at least catch any invocation of
rm [flags] /
I mean, there is no valid reason you'd ever want to do this anyway. If an ubuntu user is trying to do this, it is almost 100% certainly a mistake.
To follow Michael's much safer original suggestion, you would have wanted to make
hardware/tools
your current directory, an invoked something like
mv avr oldavr
and then copied (or linked) the newer avr toolchain into director hardware/tools/avr
That way, if the new toolchain wasn't working for you, you can delete it (or unlink it) and mv (rename) oldavr back to avr.