I have installed memcahced server in my machine
namal@namal:~$ sudo service memcached start
Starting memcached: memcached.
namal@namal:~$ telnet 127.0.0.1 11211
Connected to 127.0.0.1.
Escape character is '^]'.
namal@namal:~$ which memcached
yum update memcached
Setting up the Update Process
No Match for argument: memcached
No package memcached available.
No Packages marked for Update
aptitude show memcached
namal@namal:~$ aptitude show memcached
Automatically installed: no
Maintainer: Ubuntu Developers <email@example.com>
Uncompressed Size: 226 k
Depends: libc6 (>= 2.4), libevent-2.0-5 (>= 2.0.10-stable), libsasl2-2 (>= 2.1.24), perl, lsb-base (>= 3.2-13), adduser
Suggests: libcache-memcached-perl, libmemcached
Description: A high-performance memory object caching system
Danga Interactive developed memcached to enhance the speed of LiveJournal.com, a site which was already doing 20 million+ dynamic page views per day for 1 million users with a bunch of webservers and a bunch of database servers. memcached dropped
the database load to almost nothing, yielding faster page load times for users, better resource utilization, and faster access to the databases on a memcache miss.
memcached optimizes specific high-load serving applications that are designed to take advantage of its versatile no-locking memory access system. Clients are available in several different programming languages, to suit the needs of the specific
application. Traditionally this has been used in mod_perl apps to avoid storing large chunks of data in Apache memory, and to share this burden across several machines.
aptitude show memcached in the terminal. Then you might find out that the latest version currently supported by the Ubuntu 12.10 repositories is in fact 1.4.14. (You might need to install aptitude if it's not installed.)
That is because the package is maintained by the Ubuntu developers to ensure that it is stable for the Ubuntu release you are using. For more about Ubuntu repositories, see https://help.ubuntu.com/community/Repositories/Ubuntu
If you still want the latest and greatest, you might need to build it from source yourself:
Edit: Broken link, and no way to substitute it. Their wiki docs seems to be suffering after Memcached migrated to GitHub. So http://www.memcached.org/ or https://github.com/memcached/memcached might be the place to start. Hopefully, up to date install-from-source-docs will eventually show up at https://github.com/memcached/memcached/wiki.