regex - How to insert newline character after comma in `),(` with sed?

Question

How to insert newline character after comma in ),( with sed?

$ more temp.txt
(foo),(bar)
(foobar),(foofoobar)

$ sed 's/),(/),
(/g' temp.txt 
(foo),n(bar)
(foobar),n(foofoobar)

Why this doesn't work?

Answer 1

sed does not support the escape sequence in its substitution command, however, it does support a real newline character if you escape it (because sed commands should only use a single line, and the escape is here to tell sed that you really want a newline character):

$ sed 's/),(/),\
(/g' temp.txt
(foo),
(bar)
(foobar),
(foofoobar)

You can also use a shell variable to store the newline character.

$ NL='
'
$ sed "s/),(/,\$NL(/g" temp.txt
(foo),
(bar)
(foobar),
(foofoobar)

Tested on Mac OS X Lion, using bash as shell.