Execute commands properly. You can see what's happening, and errors halt the build

Rakefile

@@ -16,7 +16,7 @@ task :commonjs do
   puts "Packaging for CommonJS"
   source = "mustache-commonjs"
   target_jq = "commonjs.mustache.js"
-  `cat #{source}/#{target_jq}.tpl.pre mustache.js #{source}/#{target_jq}.tpl.post > #{target_jq}`
+  sh "cat #{source}/#{target_jq}.tpl.pre mustache.js #{source}/#{target_jq}.tpl.post > #{target_jq}"
   puts "Done."
 end
 
@@ -25,7 +25,7 @@ task :jquery do
   puts "Packaging for jQuery"
   source = "mustache-jquery"
   target_jq = "jquery.mustache.js"
-  `cat #{source}/#{target_jq}.tpl.pre mustache.js #{source}/#{target_jq}.tpl.post > #{target_jq}`
+  sh "cat #{source}/#{target_jq}.tpl.pre mustache.js #{source}/#{target_jq}.tpl.post > #{target_jq}"
   puts "Done, see ./#{target_jq}"
 end
 
@@ -34,8 +34,8 @@ task :dojo do
   puts "Packaging for dojo"
   source = "mustache-dojo"
   target_js = "mustache.js"
-  `mkdir -p dojox; mkdir -p dojox/string`
-  `cat #{source}/#{target_js}.tpl.pre mustache.js #{source}/#{target_js}.tpl.post > dojox/string/#{target_js}`
+  sh "mkdir -p dojox; mkdir -p dojox/string"
+  sh "cat #{source}/#{target_js}.tpl.pre mustache.js #{source}/#{target_js}.tpl.post > dojox/string/#{target_js}"
   puts "Done, see ./dojox/string/#{target_js} Include using dojo.require('dojox.string.mustache.'); "
 end
 
@@ -44,12 +44,12 @@ task :yui3 do
   puts "Packaging for YUI3"
   source = "mustache-yui3"
   target_js = "mustache.js"
-  `mkdir -p yui3; mkdir -p yui3/mustache`
-  `cat #{source}/#{target_js}.tpl.pre mustache.js #{source}/#{target_js}.tpl.post > yui3/mustache/#{target_js}`
+  sh "kdir -p yui3; mkdir -p yui3/mustache"
+  sh "cat #{source}/#{target_js}.tpl.pre mustache.js #{source}/#{target_js}.tpl.post > yui3/mustache/#{target_js}"
   puts "Done, see ./yui3/mustache/#{target_js}"
 end
 
 desc "Remove temporary files."
 task :clean do
-  `git clean -fdx`
+  sh "git clean -fdx"
 end