Ubuntu rails install fails on zlib

If you come across this question trying to install Ruby using Ruby Version Manager (RVM) on Ubuntu 10.04 then there are instructions on installing zlib on the rvm web site http://rvm.beginrescueend.com/packages/zlib/

The steps are:

rvm pkg install zlib

(or
rvm package install zlib if you get “ERROR: Unrecognized command line argument: ‘pkg'” – older versions of rvm used the verb ‘package’ instead)

then

rvm remove 1.9.1
rvm install 1.9.1