Redirect rules on change of domain name

.htaccess

# Redirect all requests from olddomain.com to www.newdomain.com

# tell the server to activate mod_rewrite
RewriteEngine On

# What's the redirect base (i.e. root or subdirectory)
RewriteBase /

# Either check if the request goes to the old domain 
RewriteCond %{HTTP_HOST} ^(www\.)?olddomain\.com$ [NC]

# Just in case you want to redirect any subdomain as well
# uncomment the following line
# RewriteCond %{HTTP_HOST} ^(.*\.)?olddomain\.com$ [NC]

# or - as a more general alternative - check if the request does 
# _not_ go to the _new_ domain (just comment/uncomment the condition) 
# RewriteCond %{HTTP_HOST} !^(www\.)?newdomain\.com$ [NC]

RewriteRule .* http://www.newdomain.com%{REQUEST_URI} [R=301,L]

# Redirect end

This was asked in the LinkedIn group Wordpress Experts
https://www.linkedin.com/groups/Need-help-301-redirects-1482937.S.5962641276233859073?view=&item=5962641276233859073