gem commands
* help gem -h gem environment gem help example gem help platforms gem help search * list up gem pack(first char is 'r') gem list r * inst/uninst/update gem insall rails gem update erubis gem uninsall sshexpect * search with :-d detail :-r remote gem search -r -d expect gem search -r -d httpclient gem search -r -d sshexpect gem search evil --remote * start RDoc presentation web server gem server --port 8808 --no-daemon