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

i would do this with an awk script:

BEGIN {i=0}
(i==0) && /#include/ {print "#include \"newfile.h\""; i=1}
{print $0}    
END {}

then run it with awk:

awk -f awkscript headerfile.h > headerfilenew.h

might be sloppy, I'm new to this.