http://stackoverflow.com/questions/818255/in-the-bash-shell-what-is-21
echo test > afile.txt
..redirects stdout to afile.txt. This is the same as doing..
echo test 1> afile.txt
To redirect stderr, you do..
echo test 2> afile.txt
>& is the syntax to redirect a stream to another file descriptor - 0 is stdin. 1 is stdout. 2 is stderr.
You can redirect stdin to stderr by doing..
echo test 1>&2 # or echo test >&2
..or vice versa:
echo test 2>&1
So, in short.. 2> redirects stderr to an (unspecified) file, appending &1 redirects stderr to stdout