Use sed to change conf file

Question

I'm trying to set some numeric values in my nginx.conf file. I'm calling sed from the RUN command in my Dockerfile.

Specifically I'm wanting to change what is currently:

worker_processes 4;

To:

worker_processes 1;

Regular expressions are powerful, but $*(&(*Y hard to make work.

I found this, which works.

 sed -i '/access_log/s|/[^;]\+|/dev/stdout|' /etc/nginx/nginx.conf

But modified to this and it doesn't.

 sed -i '/worker_processes/s|/[^;]\+|1|' /etc/nginx/nginx.conf

If someone could explain how the expression works the first time and not the second and how to make it work, that'd be great.

Answer 1

This worked for me in the end.

sed -i 's/^worker_processes.*/worker_processes 1;/' /etc/nginx/nginx.conf