what does $route['(:any)'] = 'pages/view/$1'; mean in Codeigniter Router

$route['(:any)'] = 'pages/view/$1'; means that anything you type on the url will proceed to pages/view/$1 the $1 here is the parameter you would like to pass to a controller/method example

$route['login/(:any)'] = 'home/bacon/$1';

in this example you are telling CI that anything that goes to login with any parameter like login/john will proceed to your home/bacon/john (:any) will match all string and integer if you use (:num) it will only match integer parameters like

$route['login/(':num')'] = 'home/bacon/$1'

in this config you are specifying that if a url login has a integer after it like login/1234, you would like it to redirect to home/bacon/1234 if you don't know how many parameters you would like to pass you could try $route['login/(:any).*'] = 'home/bacon/$1' more on this could be read at https://www.codeigniter.com/user_guide/general/routing.html

$1 would be whatever matched by (:any) group - which is, really, anything. Whatever you add will get passed as the parameter for view method in pages controller.

More here on routing with codeigniter.