How can I remove a line-feed/newline BEFORE a pattern using sed

Question

The title already states it:

I want to use some linux one liner (e.g. sed)

to transform

Anytext
{

into

Anyt         


        

Answer 1

Using awk

cat file
one
Anytext
{
two
three
{
four
five
{

awk '{printf (!/^{/&&NR>1?RS:x)"%s",$0} END {print ""}' file
one
Anytext{
two
three{
four
five{