# 4 tabs
cat $1      | sed 's/^				\([^	]\)/            \1/g' > $1.tmp
# 3 tabs
cat $1.tmp  | sed 's/^			\([^	]\)/            \1/g' > $1.tmp2
# 2 tabs
cat $1.tmp2 | sed 's/^		\([^	]\)/      \1/g' > $1.tmp
# 1 tab
cat $1.tmp  | sed 's/^	\([^	]\)/   \1/g' > $1.tmp2
rm $1.tmp
echo done: $1.tmp2