Basic RewriteBase question...

my site is in a path like this: http://localhost/mysite

there are two files: http://localhost/mysite/1.txt and
http://localhost/mysite/2.txt

I want to redirect from 1.txt to 2.txt using mod_rewrite, my .htaccess
file is this:

RewriteEngine On
RewriteRule ^1.txt$ /mysite/2.txt

(the .htaccess file is under /mysite folder)

this works fine, but obviously I'm not happy with the folder name
being hardcoded in the rule, i'd like something like this:

RewriteRule ^1.txt$ /2.txt

but it doesn't work.

adding "RewriteBase /mysite" doesnt help.

I now I'm doing something very wrong. Any help please?

thx