Q: gem -v command not found - CentOS 6.3 I'm trying to install Ruby on CentOS 6.3 I've installed the ruby-1.9.3-p286 from source. However once completed, I tried doing gem -v to verify that gems was installed and I get  /usr/bin/gem: No such file or directory. I thought this version of ruby would have automatically installed gems. Am I doing something wrong?

A: Unless you supplied a --prefix directory before building it, Ruby (at least that version - couldn't say for sure about other versions) will install things in /usr/local. That would mean gem lives at /usr/local/bin/gem.
If that file is there, you might want to consider adding /usr/local/bin to your path:
# ~/.bashrc (or equivalent):
export PATH=/usr/local/bin:$PATH

