What language is the file from which you are removing comments? The fact that you say it has "echo" statements makes me think "shell", but shells do not support "/*....*/" style comments.

Regardless of language, it's quite a leap to say that's it's obvious that comments containing "echo" should be retained. If you were told to remove all comments then that it what you should do. Maybe you should clarify your instructions.

I haven't tried it, but the first sed script you posted looks like it should work. It's pretty clever actually. But you can't split it up into separate sed statements. It's a unit and it needs to stay that way.

/\/\*/!b Loop until we find a line with "/*" in it. Once we find such a line we can proceed to the the rest of the sed script.

Code:

:x
/\*\//!{
N
bx
}

This little paragraph asks if we have a "*/". We might if the earlier sed statement found a one line comment. But if the comment extends to several lines, we will not immediately have the terminating "*/". So read read another input line with the "N" command. The "bx" jumps back to the ":x". That is how we loop in sed. Eventually we will read the "*/" and fall out of the loop to the final statement.

Code:

# delete /*...*/
s/\/\*.*\*\///

The comment is correct. It deletes the "/*...*/" comment. If all you have is one line comments, this one command may be all you need.

I have not tested it. But it all looks good. But each statement depends on the others. You are not going to be able to turn this sed script into several sed scripts. I hope this helps you.