How to append multi-lines to file in a dockerfile? [duplicate] - bash

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I have a dockerfile and can't seem to be able to embed the nginx configuration file to it, so that it can be appended to /etc/nginx/nginx.conf.
I tried the following formats:
RUN cat <<EOT >> /etc/nginx/nginx.conf
user www;
worker_processes auto; # it will be determinate automatically by the number of core
error_log /var/log/nginx/error.log warn;
pid /var/run/nginx.pid; # it permit you to use /etc/init.d/nginx reload|restart|stop|start
events {
worker_connections 1024;
}
http {
include /etc/nginx/mime.types;
default_type application/octet-stream;
sendfile on;
access_log /var/log/nginx/access.log;
keepalive_timeout 3000;
server {
listen 80;
root /usr/local/www;
index index.html index.htm;
server_name localhost;
client_max_body_size 32m;
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root /var/lib/nginx/html;
}
}
}
EOT
and
RUN echo $
'user www; \n
worker_processes auto; # it will be determinate automatically by the number of core \n
error_log /var/log/nginx/error.log warn; \n
pid /var/run/nginx.pid; # it permit you to use /etc/init.d/nginx reload|restart|stop|start \n
events { \n
worker_connections 1024; \n
} \n
http { \n
include /etc/nginx/mime.types; \n
default_type application/octet-stream; \n
sendfile on; \n
access_log /var/log/nginx/access.log; \n
keepalive_timeout 3000; \n
server { \n
listen 80; \n
root /usr/local/www; \n
index index.html index.htm; \n
server_name localhost; \n
client_max_body_size 32m; \n
error_page 500 502 503 504 /50x.html; \n
location = /50x.html { \n
root /var/lib/nginx/html; \n
} \n
} \n
}'
> /etc/nginx/nginx.conf
However with either of the two examples I get the following error, which kinda looks like docker is trying to treat the nginx config file as its own variables:
Sending build context to Docker daemon 33.28 kB
Error response from daemon: Unknown instruction: WORKER_PROCESSES
Docker version is 1.13.1, build 07f3374/1.13.1 and the distro I am using is CentOS Atomic Host 7.1902, while docker base image is alpinelinux.
Thanks

Answer 1

That should do the trick:
RUN echo $'first line \n\
second line \n\
third line' > /etc/nginx/nginx.conf
Basically it's wrapped in a $'' and uses \n\ for new lines.

Answer 2

I was looking to create & append lines to my .npmrc to install private packages. The only syntax that worked for me was:
RUN echo #myscope:registry=https://gitlab.com/api/v4/packages/npm/ > .npmrc \
&& echo //gitlab.com/api/v4/packages/npm/:_authToken=${MY_TOKEN} >> .npmrc \
&& echo strict-ssl=false >> .npmrc