I just had the same problem on Ubuntu Server 14.04.
postgis extension from the official ubuntu repositories.
So I used
# apt-get install postgis.
find /usr -name postgis.control didn't return any result.
The reason was
extension/postgis.control wasn't installed because of postgis-scripts wasn't.
$ aptitude search postgis
i libpostgis-java - Geographic objects support for PostgreSQL -- JDBC support
i postgis - Geographic objects support for PostgreSQL
p postgis:i386 - Geographic objects support for PostgreSQL
i postgis-doc - Geographic objects support for PostgreSQL -- documentation
i postgresql-9.3-postgis-2.1 - Geographic objects support for PostgreSQL 9.3
p postgresql-9.3-postgis-2.1:i386 - Geographic objects support for PostgreSQL 9.3
i postgresql-9.3-postgis-2.1-scripts - PostGIS for PostgreSQL 9.3 -- scripts -- dummy package
i postgresql-9.3-postgis-scripts - Geographic objects support for PostgreSQL 9.3 -- scripts
The solution is to install it.
On debian likes distros :
# apt-get install postgis*
The aptitude package manager will determinate automaticaly the correct package versions to install. The postgis-doc will be installed too.
You can check to succes of the operation running the following command :
$ find /usr -name postgis.control
On my server, it returns now :
You can now enable the extension on any database on your postgres server :
- connect to your db with superuser (postgres by default)
CREATE EXTENSION postgis;
Your public shema now contains all postgis object and functions.