Check whether `eget` is installed or not, before the actual installation.

cookbooks/base/eget.rb

@@ -1,7 +1,14 @@
+result = run_command('which eget',  error: false)
+if result.exit_status != 0
+  # Install eget
   execute 'curl https://zyedidia.github.io/eget.sh | sh' do
-  not_if 'which eget'
     cwd '/usr/local/bin/'
   end
 
   execute 'chown root:root /usr/local/bin/eget'
   execute 'chmod 755 /usr/local/bin/eget'
+end
+
+%w( zyedidia/eget mgdm/htmlq ).each do |p|
+  execute "eget #{p} --to /usr/local/bin/ --upgrade-only"
+end