This might not be a universal rule, but thus far it seems to hold true for me. When installing development libraries on an Ubuntu/Debian machine, you tend to use “dev”, as in “sudo apt-get zlib-dev”. When you are on a Centos/Redhat (RPM) machine, you tend to use “devel” as in “yum install zlib-devel”.
This caused me no small amount of annoyance as I was installing Rails on CentOS today, getting all sorts of zlib and openssl errors, and whenever I did a”yum install zlib-dev” it would just say “Nothing to do”, which stupid me was taking to mean “This library is already installed.”
No, apparently it means “That’s not the name of a package I recognize.” When I did “yum install zlib-devel” it came right up and solved all my problems.