mod rewrite - .htaccess RedirectMatch is OK to remove part from url? -

i want redirect url:

domain.asd/category/node123/attachment/file123 

to one:

domain.asd/category/node123 

by removing attachment/fn1aa end.

only node123 , file123 dynamic.

the code below working, it's valid, safe , resource-friendly?

redirectmatch permanent category(.*)attachment /category/$1 

any recommendation welcome. thx.

try:

redirectmatch permanent ^/category/([^/]+)/attachment /category/$1 

it's more strict , won't duplicate forward slashes (/). regex match things this:

domain.asd/foo/something/category/a/b/c/d/e/f/some-attachment 

by redirecting to:

/category//a/b/c/d/e/f/some- 

which isn't want do. it's safe , resource friendly using htaccess file (which slight performance hit opposed putting in vhost config).