httaccess redirect to new URL with conditions

Question

Trying to create a htaccess file that redirects to new URL but with conditions based on the beginning value of the URI. For example:

if

example.com/piasjgasngan will redirect to http://example2.com/index.php?id=paiajgasngan

( the first letter of p in the uri will be the condition topass to the new URL )

if

example.com/x9q8wutjgj will redirect to URL example2.com/download_app.html

( the first letter of x in the uri will be the condition )

else all other URI will rediect to a different URL

example.com/89qwtjggjqa will redirect to example2.com/invalid_URI.html

I have tried numerous different conditions

RewriteEngine On
RewriteCond %{HTTPS} off
RewriteCond %{HTTP_HOST} !^(www\.)?example\.com$ [NC]
RewriteCond ^p$ [NC]
RewriteRule .* http://example2.com\P\index.php=id={REQUEST_URI} [R=301,NC,OR]
RewriteCond ^x$ [NC]
RewriteRule .* http://example2.com\download_app.html [R=301,NC,OR]
RewriteRule .* http://example2.com\bad_URI.html [R=301,L]

all attempts send to example.com/download_app.html

Hope my example identifies the what I am trying to accomplish TY in advance

Answer 1

Could you please try following, written based on your shown samples. Please make sure you clear your browser cache before testing your URLs.

RewriteEngine ON
##First character is p OR x of URI condition.
RewriteCond %{HTTP_HOST} example\.com [NC]
RewriteCond %{REQUEST_URI} ^/(p|x)(.*)/?$ [NC]
RewriteRule ^(.)$ http://example2.com/index.php?id=%1%2 [L]

##Anything else uri condition.
RewriteCond %{HTTP_HOST} example\.com [NC]
RewriteRule ^(.*)$ http://example2.com/invalid_URI.html [L]