Parsing of parenthesis with sed using regex

Question

I am looking for a command in sed which transforms this input stream:

dummy
(key1)
(key2)dummy(key3)
dummy(key4)dummy
dummy(key5)dummy))))dummy
         


        

Answer 1

Perlishly I'd do:

my @all_keys; 

while (  ) {
   push ( @all_keys, m/\((.+?)\)/g  );
}
print join ("\n",@all_keys);


__DATA__
dummy
(key1)
(key2)dummy(key3)
dummy(key4)dummy
dummy(key5)dummy))))dummy
dummy(key6)dummy))(key7)dummy))))

This assumes that 'keys' match the \w in perlre (alphanumeric plus "_",)

(If you're not familiar with perl, you can pretty much just swap that for and pipe the data straight to your script - or do more interesting things with @all_keys)