UNIX/Linux noob of over 30 years!!!
But I'm really new to Raspbian!
So how does this happen.
I download the latest SDL2 tar build. I use the desktop archive utility to look inside and the is a executable in /usr/local/bin a couple of libs in /usr/local/lib some include files in /usr/local/include/SDL2. All looks good. All files in the archive have the full path.
Now I want to overwrite the existing FILES that are there so I use this command to extract the files:
# cd /
# sudo tar xvf ~/Downloads/sdl-raspberrypi-3085.tar.xz
That was all it took to blow away every file in the /usr/local/bin
So every command after that was missing. Lucky I remember cd and echo are built into the shell.
# cd /usr/local/bin
# echo *
The only file remaining was the file extracted from the archive!
Since when did tar delete and recreate a directory before restoring files to it.
I tested this on an Ubuntu system (not as root though) and it certainly doesn't!