persistent process

Hi!

What do you think is the best way to kill this process:

export a='((echo -n "export a='"'"'"
echo -n "$a"|sed '"'"'s/'"'"'"'"'"'"'"'"'/&"&"&/g'"'"'
echo "'"'"'
$a")|sh)/dev/null 2>/dev/null&'
echo "$a"|sh

Many thanks!

Stephen