How to use sed to replace only the first occurrence in a file?

Question

I would like to update a large number of C++ source files with an extra include directive before any existing #includes. For this sort of task, I normally use a small bash s

Answer 1

A possible solution:

    /#include/!{p;d;}
    i\
    #include "newfile.h"
    :a
    n
    ba

Explanation:

• read lines until we find the #include, print these lines then start new cycle
• insert the new include line
• enter a loop that just reads lines (by default sed will also print these lines), we won't get back to the first part of the script from here