Simple .htaccess example:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteRule ^lookup/([a-z0-9\-]+)/item/?$ /lookup.php?id=$1
</IfModule>
This will match any alphanumeric (also will recognise dashes) string of any length as the ‘id’. You can limit this to just numeric by changing the regex to ([0-9]+)
.
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteRule ^lookup/([a-z0-9\-]+)/([a-z0-9\-]+)/?$ /lookup.php?id=$1&view=$2
</IfModule>
This one will match /lookup/123/some-text/
to /lookup.php?id=123&view=some-text