htaccess rewrite rule without slash - .htaccess

Question

I am trying and googling for hours now and can't find a solution for my problem. I want to rewrite:
domain.com/profile.php?user=abc > domain.com/abc
I use:
RewriteRule ^(.*)/$ /profile.php?user=$1 [L]
which works only with a slash at the end. If i try it without the slash
RewriteRule ^(.*)$ /profile.php?user=$1 [L]
I get an Internal Server Error!
Complete .htaccess
ErrorDocument 404 /errors/404.php
ErrorDocument 500 /errors/500.php
RewriteEngine On
RewriteCond %{HTTP_HOST} ^www\.domain\.com$ [NC]
RewriteCond %{REQUEST_URI} !\.(css|jpg|gif|png|jar|js|html|htm|php)$
RewriteRule ^(.*)$ http://domain.com/$1 [L,R=301]
RewriteRule ^share/([^/]*)/$ /share/share.php?id=$1 [L]
RewriteRule ^(.*)/$ /profile.php?user=$1 [L]
<IfModule mod_deflate.c>
<FilesMatch "\.(html|php|txt|xml|js|css|svg)$">
SetOutputFilter DEFLATE
</FilesMatch>
</IfModule>
BrowserMatch ^Mozilla/4\.0[678] no-gzip
BrowserMatch \bMSIE\s7 !no-gzip !gzip-only-text/html
Someboy have an idea what Im doing wrong?
Thanks,
Kornel

Answer 1

With your second try, you get a 500 because you create an infinite loop:
^(.*)$ will match profile.php?user=xxx again and again... Which is not the case when you try with ^(.*)/$ because (no trailing slash) this won't match profile.php?user=xxx
Instead, you can have it this way
RewriteEngine On
RewriteCond %{HTTP_HOST} ^www\.domain\.com$ [NC]
RewriteCond %{REQUEST_URI} !\.(css|jpg|gif|png|jar|js|html|htm|php)$
RewriteRule ^(.*)$ http://domain.com/$1 [L,R=301]
RewriteRule ^share/([^/]*)/$ /share/share.php?id=$1 [L]
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)/?$ /profile.php?user=$1 [L]