.htaccess cans and can'ts - .htaccess

Question

I am very new to the idea of .htaccess and thought that it was what you used to do something like turn this:
http://www.domain.com/some/ugly/url/here.html
into this:
http://www.domain.com/niceurl
I was just told by my ISP that in order to get that to happen, no, it's done by putting the document into the web root folder. That .htaccess isn't used at all.
Does anyone know if this is true? I see a lot of examples about what .htaccess DOES but not so much about what it can't do. Somehow I thought this was all that was needed.
Lastly, if someone types in www.domain.com/niceurl what will happen? Don't I need to have that linked (if not by htaccess, how?!) to the location of the actual file?
Thank you for any and all help. I realize that .htaccess questions abound but they're hard to pick through for the layperson and I'm hoping to answer this specific question.

Answer 1

Here's what I believe should be an answer you want, put the block below to your .htaccess
Answer:
## Enabling Apache's Mod_rewrite module.
RewriteEngine On
# Following line is required if your webserver's URL is not directly related to physical file paths (just / for root, e.g. www.domain.com/)
RewriteBase /
# Restricts rewriting URLs only to paths that do not actually exists
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
# Redirect www.domain.com/bar to www.domain.com/foo
Redirect 301 /bar /foo
# Internally load the long URL without changing URL in address bar
RewriteRule ^foo/?$ http://www.domain.com/some/ugly/long/thing/here.html [L,NC]
As a result, www.domain.com/bar will be redirected to www.domain.com/foo and /foo will internally load http://www.domain.com/some/ugly/long/thing/here.html
FYI:
Your website's URL doesn't have to be directly related to physical file paths. Your URL's segment can be served as alias to your URL's parameters. for e.g,
http://www.domain.com/index.php?key1=value1&key2=value2
can be represented as
http://www.domain.com/value1/value2
Note: you need to implement a server side script to be served as a
router to manipulate the URL segments.
For more information about using .htaccess, check this out
Ref: http://htaccess-guide.com/
.htaccess files can be used to alter the configuration of the Apache Web Server software to enable/disable additional functionality and features that the Apache Web Server software has to offer. These facilities include basic redirect functionality, for instance if a 404 file not found error occurs, or for more advanced functions such as content password protection or image hot link prevention.
Below is a few examples,
# Custom Error Pages for Better SEO,
# for e.g, to handle 404 file not found error
ErrorDocument 404 http://www.domain.com/404page.html
# Deny visitors by IP address
order allow,deny
deny from 122.248.102.86
deny from 188.40.112.210
allow from all
# Redirects
Redirect 302 /en/my-dir/my-page.html /en/my-path/example.html
# Disallow some silly bots from crawling your sites
RewriteCond %{HTTP_USER_AGENT} (?i)^.*(BlackWidow|Bot\\ mailto:craftbot#yahoo.com|ChinaClaw|Custo|DISCo|Download\\ Demon|eCatch|EirGrabber|EmailSiphon|EmailWolf|Express\\ WebPictures|ExtractorPro|EyeNetIE|FlashGet|GetRight|GetWeb!|Go!Zilla|Go-Ahead-Got-It|GrabNet).*$
RewriteRule .* - [R=403,L]
# Setting server timezone
SetEnv TZ America/Los_Angeles
# trailing slash enforcement,
# e.g, http://www.domain.com/niceurl to http://www.domain.com/niceurl/
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_URI} !#
RewriteCond %{REQUEST_URI} !(.*)/$
RewriteRule ^(.*)$ http://www.domain.com/$1/ [L,R=301]

Answer 2

Enable mod_rewrite and .htaccess through httpd.conf (if not already enabled) and then You can use this code in your DOCUMENT_ROOT/.htaccess file:
RewriteEngine On
RewriteRule ^niceurl/?$ some/ugly/url/here.html [L,NC]
This will allow you to use http://domain.com/niceurl in your browser and it will internally load http://domain.com/some/ugly/url/here.html without changing URL in browser.
If you also want to force redirection from ugly URL to pretty URL then add this redirect rule just below RewriteEngine On line:
RewriteCond %{THE_REQUEST} \s/+some/ugly/url/here\.html [NC]
RewriteRule ^ /niceurl [R=302,L,NE]