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

Issue

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 script with sed to re-write the file.

How do I get sed to replace just the first occurrence of a string in a file rather than replacing every occurrence?

If I use

sed s/#include/#include "newfile.h"\n#include/

it replaces all #includes.

Alternative suggestions to achieve the same thing are also welcome.

Solution

 # sed script to change "foo" to "bar" only on the first occurrence
 1{x;s/^/first/;x;}
 1,/foo/{x;/first/s///;x;s/foo/bar/;}
 #---end of script---

or, if you prefer: ^{Editor's note: works with GNU sed only.}

sed '0,/foo/s//bar/' file 

Source

Answered By - Ben Hoffstein

Answer Checked By - David Goodson (WPSolving Volunteer)