As a configuration file, .htaccess is very powerful.  Even the slightest syntax error can result in your content not displaying correctly or at all.

Check the mostly used ones:

• Point an entire site to a different URL, such as domain.net redirected to domain.com:

  # This allows you to redirect your entire website to any other domain
  Redirect 301 / http://kb.mediatemple.net/

• Redirect index.html to a specific subfolder:

  # This allows you to redirect index.html to a specific subfolder
  Redirect /index.html http://mt-example.com/newdirectory/
  

• Redirect an old file to a new file path:

  # Redirect old file path to new file path
  Redirect /olddirectory/oldfile.html http://mt-example.com/newdirectory/newfile.html

• Redirect to a specific index page:

  # Provide Specific Index Page (Set the default handler)
  DirectoryIndex index.html

• Redirect users to access the site without www:

  # To redirect all users to access the site WITHOUT the www. prefix,
  # (http://www.example.com/... will be redirected to http://example.com/...)
  # adapt and uncomment the following:
  
  RewriteEngine On
  RewriteCond %{HTTP_HOST} ^www\.mt-example\.com$ [NC]
  RewriteRule ^(.*)$ http://mt-example.com/$1 [L,R=301]

• Redirect users to use www:

  # To redirect all users to access the site WITH the www. prefix,
  # (http://example.com/... will be redirected to http://www.example.com/...)
  # adapt and uncomment the following:
  
  RewriteEngine On
  RewriteCond %{HTTP_HOST} !^www\.mt-example\.com$ [NC]
  RewriteRule ^(.*)$ http://www.mt-example.com/$1 [L,R=301]

Happy Bookmarking!