Postgresql - Having a portable database on an external hard drive usable by many computers

I want to know if it is possible to have a portable Postgresql database on an external hard drive. The idea is to use that hard drive, by plugging it to one of my computers and use the database. *For the moment, it is not possible for me to have a computer that is always running and connecting to it through the network. For some reasons I don't always have access to the same computer but I always have access to my external hard drive. The computers are both running a Linux distribution.*