Merge pull request cheat#51 from luathn/add-ruby-gem-cheatsheets

Add ruby and gem cheatsheet

gem

@@ -0,0 +1,29 @@
+---
+tags: [ packaging, ruby ]
+---
+# To search for a package:
+gem search <package>
+
+# To install a package:
+gem install <package>
+
+# To install a package in user space:
+gem install --user-install <package>
+
+# To install specific version of a package:
+gem install <package> -v <version>
+
+# To uninstall a package:
+gem uninstall <package>
+
+# To upgrade a package:
+gem update <package>
+
+# To show details of a package:
+gem info <package>
+
+# To list local packages:
+gem list --local
+
+# To show help on command:
+gem help <command>

ruby

@@ -0,0 +1,19 @@
+# Ruby - Interpreted object-oriented scripting language
+# Main page: https://www.ruby-lang.org/
+# Help and documentation: https://ruby-doc.org/
+
+# To serve the current directory:
+ruby -run -e httpd . -p <port>
+
+# To execute a script file:
+ruby <file>
+
+# To execute one line of script:
+ruby -e 'command'
+
+# To check script file syntax:
+ruby -c <file>
+
+# To specify $LOAD_PATH directory:
+ruby -Idirectory
+ruby -Ispec spec/test_spec.rb