Redirect both / and non-/ URLs?

[OVJ]

I am doing SEO on WP site. Due to some duplicate pages (rel canonical was done before) I am doing 301 redirects at the moment. And I wonder if I need to redirect both links w/ and w/o trailing slash. Default is non www, w/o trailing slash.

Like there is .com/category/news but there is same page linked in .com/news (well it works when permalink structure is set to /%category%/%postname% and returns 404 error when structure is set to /%postname%). 
I redirected .lt/naujienos to .lt/category/naujienos. Should I also redirect .lt/naujienos/ (with trailing slash)?

There's absolutely no problem redirecting this, but there are some more pages which I want to edit their URLs and I wonder If I should do both redirects from links /w and w/o slash?

[OVJ]

There is my .htaccess at the moment:

<ifmodule mod_rewrite.c="">RewriteEngine On
RewriteBase /
RewriteRule ^index.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]</ifmodule>

I don't want to mess with it because I don't have an access to cpanel.

[OVJ]

Well, I want non-trailing URLs as they are at the moment. They should be (the ones without trailing slash) rel canonical as they were before I changed permalink structure ( it was set to default: /?p=123) to /%postname%

I guess I will wait a crawl to see how it is at the moment and fix all those pages with 404.

BTW, google shows my site and pages with /. Maybe it hasn't recrawled yet.

[Sturge]

Another option would be to add another re-direct rule that would add a trailing slash to all of the URLS.
So effectively, if you re-direct the non-trailing URLS all URLS would then have a trailing slash.

RewriteCond %{REQUEST_URI} !.[^./]+$
RewriteCond %{REQUEST_URI} !(.)/$
RewriteRule ^(.)$ /$1/ [R=301,L]

Give this a try maybe? Just ensure that the REL Canonical reflects the URLS WITH the trailing slash otherwise you will get stuck in a canonical loop.

Craig Curchin
Twitter: @craigcurchin

[Chris.Menke]

Fisher,

Google deals with both with / and without / as though they are the same thing so I wouldn't worry about redirecting those.  If visitors normally get a trailing slash, canonicalize that, if they don't canonicalize on the URL without the slash.

http://www.mattcutts.com/blog/seo-advice-url-canonicalization/