How to correctly set up a redirect to an address without a slash?

Question

htaccess

It is necessary that a redirect be carried out from an address of the form site.ru/ to site.ru
Please tell me how to register correctly

Options -Indexes 
ErrorDocument 404 /404.php

<IfModule mod_php5.c>
  php_flag session.use_trans_sid off
  #php_value display_errors 1
  #php_value mbstring.internal_encoding UTF-8
</IfModule>

<IfModule mod_rewrite.c>
  Options +FollowSymLinks
  RewriteEngine On
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteCond %{REQUEST_FILENAME} !-l
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteCond %{REQUEST_FILENAME} !/bitrix/urlrewrite.php$
  RewriteRule ^(.*)$ /bitrix/urlrewrite.php [L]
  RewriteRule .* - [E=REMOTE_USER:%{HTTP:Authorization}]
</IfModule>

<IfModule mod_dir.c>
  DirectoryIndex index.php index.html
</IfModule>

<IfModule mod_expires.c>
  ExpiresActive on
  ExpiresByType image/jpeg "access plus 3 day"
  ExpiresByType image/gif "access plus 3 day"
  ExpiresByType image/png "access plus 3 day"
  ExpiresByType text/css "access plus 3 day"
  ExpiresByType application/javascript "access plus 3 day"  
</IfModule>

Options +FollowSymLinks
RewriteEngine On
RewriteCond %{HTTP_HOST} ^www.site\.ru$ [NC]
RewriteRule ^(.*)$ http://site.ru/$1 [R=301,L]

RewriteCond %{REQUEST_URI} ^(.*)/index\.php$
RewriteRule ^(.*)index\.php$ http://%{HTTP_HOST}/$1 [R=301,L]

Answer 1

The problem is more complicated than it seems, because in these redirects, for good, you still need to track the status of the recipient, because if there is 404, then there is no point in changing it to 301 + 404, and from the point of view of SEO, this is not feng shui.
Removes multiple slashes in the url if they occur like //

RewriteCond %{REQUEST_URI} !\..+$
RewriteCond %{REQUEST_URI} .*\/\/$
RewriteRule (.*)(\/\/)(.*)$ $1/$3$

Excluding files by mask, since you don't need to put a slash at the end of the files, since the -f directive will not work properly here. You can also replace it with any point, in principle, except for files, it does not occur anywhere. But I personally limited so.
H

RewriteCond %{REQUEST_FILENAME} !^.+\.(jpg|jpeg|gif|png|ico|css|zip|tgz|gz|rar|bz2|doc|xls|exe|pdf|ppt|txt|tar|mid|midi|wav|bmp|rtf|js|swf|flv|mp3)$
RewriteCond %{REQUEST_URI} !(.*)/$
RewriteRule ^(.*[^/])$ $1/ [L,R=301]

Also, do not forget that you need to put this after the cnc