<html><head><meta http-equiv="Content-Type" content="text/html; charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Hi:<div class=""><br class=""></div><div class="">After I updated macOS Catalina, Markdown Preview no longer works. I got the following error message:</div><div class=""><br class=""></div><div class=""><span style="font-family: "Trebuchet MS", Helvetica, sans-serif; font-size: 13px; background-color: rgb(255, 255, 255);" class="">Please install the Redcarpet and Pygments.rb RubyGems by running the following:</span></div><div class=""><pre id="scroll_to_here" style="font-size: 12.350000381469727px; font-family: LuxiMono, "Bitstream Vera Sans Mono", Menlo, Monaco, "Courier New", monospace; word-wrap: break-word; white-space: pre-wrap; padding: 10px 10px 10px 20px; background-color: rgb(240, 240, 240); border: 1px solid rgb(204, 203, 186);" class=""><code style="font-size: 11.732500076293945px; font-family: LuxiMono, "Bitstream Vera Sans Mono", Menlo, Monaco, "Courier New", monospace; word-wrap: break-word; color: rgb(28, 54, 12); margin-top: 0px;" class="">/usr/bin/gem install --user redcarpet pygments.rb</code></pre><div class=""><br class=""></div></div><div class="">After I ran the above command, I received the following error message from the Terminal:</div><div class=""><br class=""></div><div class=""><div style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; color: rgb(59, 35, 34); background-color: rgb(215, 211, 183);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class="">$ /usr/bin/gem install --user redcarpet pygments.rb</b></span></div><div style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; color: rgb(59, 35, 34); background-color: rgb(215, 211, 183);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class="">Building native extensions. This could take a while...</b></span></div><div style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; color: rgb(59, 35, 34); background-color: rgb(215, 211, 183);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class="">ERROR: Error installing redcarpet:</b></span></div><div style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; color: rgb(59, 35, 34); background-color: rgb(215, 211, 183);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class=""><span class="Apple-tab-span" style="white-space:pre"> </span>ERROR: Failed to build gem native extension.</b></span></div><div style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; color: rgb(59, 35, 34); background-color: rgb(215, 211, 183); min-height: 14px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class=""></b></span><br class=""></div><div style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; color: rgb(59, 35, 34); background-color: rgb(215, 211, 183);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class=""> current directory: /Users/tzha/.gem/ruby/2.6.0/gems/redcarpet-3.5.0/ext/redcarpet</b></span></div><div style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; color: rgb(59, 35, 34); background-color: rgb(215, 211, 183);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class="">/System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/bin/ruby -I /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0 -r ./siteconf20191111-836-11oqvm2.rb extconf.rb</b></span></div><div style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; color: rgb(59, 35, 34); background-color: rgb(215, 211, 183);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class="">mkmf.rb can't find header files for ruby at /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/include/ruby.h</b></span></div><div style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; color: rgb(59, 35, 34); background-color: rgb(215, 211, 183); min-height: 14px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class=""></b></span><br class=""></div><div style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; color: rgb(59, 35, 34); background-color: rgb(215, 211, 183);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class="">You might have to install separate package for the ruby development</b></span></div><div style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; color: rgb(59, 35, 34); background-color: rgb(215, 211, 183);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class="">environment, ruby-dev or ruby-devel for example.</b></span></div><div style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; color: rgb(59, 35, 34); background-color: rgb(215, 211, 183); min-height: 14px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class=""></b></span><br class=""></div><div style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; color: rgb(59, 35, 34); background-color: rgb(215, 211, 183);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class="">extconf failed, exit code 1</b></span></div><div style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; color: rgb(59, 35, 34); background-color: rgb(215, 211, 183); min-height: 14px;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class=""></b></span><br class=""></div><div style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; color: rgb(59, 35, 34); background-color: rgb(215, 211, 183);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class="">Gem files will remain installed in /Users/tzha/.gem/ruby/2.6.0/gems/redcarpet-3.5.0 for inspection.</b></span></div><div style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; color: rgb(59, 35, 34); background-color: rgb(215, 211, 183);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class="">Results logged to /Users/tzha/.gem/ruby/2.6.0/extensions/universal-darwin-19/2.6.0/redcarpet-3.5.0/gem_make.out</b></span></div><div style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; color: rgb(59, 35, 34); background-color: rgb(215, 211, 183);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class="">Successfully installed pygments.rb-1.2.1</b></span></div><div style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; color: rgb(59, 35, 34); background-color: rgb(215, 211, 183);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class="">Parsing documentation for pygments.rb-1.2.1</b></span></div><div style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; color: rgb(59, 35, 34); background-color: rgb(215, 211, 183);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class="">Done installing documentation for pygments.rb after 0 seconds</b></span></div><div style="margin: 0px; font-stretch: normal; font-size: 12px; line-height: normal; font-family: Courier; color: rgb(59, 35, 34); background-color: rgb(215, 211, 183);" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class="">1 gem installed</b></span></div></div><div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><b class=""><br class=""></b></span></div><div class="">Can someone help me to resolve this issue?</div><div class=""><br class=""></div><div class="">Thanks,</div><div class=""><br class=""></div><div class="">Tao</div></body></html>