bash - Exporting multiple line code without changes using echo / linux

Question

System CentOS 7.2 Looking for a solution to write multi line code to a file without changes

small piece form a code:

echo '
sed -i $'45 a 
' /usr/local/nagios/etc/nagios.cfg &&
sed -i $'45 a 
' /usr/local/nagios/etc/nagios.cfg &&
sed -i $'45 a 
' /usr/local/nagios/etc/nagios.cfg &&
sed -i '46s#.*#cfg_file=/usr/local/nagios/etc/hosts.cfg#' /usr/local/nagios/etc/nagios.cfg &&
sed -i '47s#.*#cfg_file=/usr/local/nagios/etc/services.cfg#' /usr/local/nagios/etc/nagios.cfg &&
sed -i $'48 a 
' /usr/local/nagios/etc/nagios.cfg &&
' >> output.sh

Desired output:

sed -i $'45 a 
' /usr/local/nagios/etc/nagios.cfg &&
sed -i $'45 a 
' /usr/local/nagios/etc/nagios.cfg &&
sed -i $'45 a 
' /usr/local/nagios/etc/nagios.cfg &&
sed -i '46s#.*#cfg_file=/usr/local/nagios/etc/hosts.cfg#' /usr/local/nagios/etc/nagios.cfg &&
sed -i '47s#.*#cfg_file=/usr/local/nagios/etc/services.cfg#' /usr/local/nagios/etc/nagios.cfg &&
sed -i $'48 a 
' /usr/local/nagios/etc/nagios.cfg &&

What I'm getting is :

sed -i $45 a n /usr/local/nagios/etc/nagios.cfg &&
sed -i $45 a n /usr/local/nagios/etc/nagios.cfg &&
sed -i $45 a n /usr/local/nagios/etc/nagios.cfg &&
sed -i 46s#.*#cfg_file=/usr/local/nagios/etc/hosts.cfg# /usr/local/nagios/etc/nagios.cfg &&
sed -i 47s#.*#cfg_file=/usr/local/nagios/etc/services.cfg# /usr/local/nagios/etc/nagios.cfg &&
sed -i $48 a n /usr/local/nagios/etc/nagios.cfg &&

as you can see Quotes are disappearing, no matter I'm using single quote or double quote with echo. may be there is an other solution than ECHO or some sort of universal brackets to keep code unchanged when writing to the file?

Answer 1

cat <<EOF >> output.sh
sed -i $'45 a 
' /usr/local/nagios/etc/nagios.cfg &&
sed -i $'45 a 
' /usr/local/nagios/etc/nagios.cfg &&
sed -i $'45 a 
' /usr/local/nagios/etc/nagios.cfg &&
sed -i '46s#.*#cfg_file=/usr/local/nagios/etc/hosts.cfg#' /usr/local/nagios/etc/nagios.cfg &&
sed -i '47s#.*#cfg_file=/usr/local/nagios/etc/services.cfg#' /usr/local/nagios/etc/nagios.cfg &&
sed -i $'48 a 
' /usr/local/nagios/etc/nagios.cfg &&
EOF