I've got this Gruntfile.js generated by yeoman-generator-angular : http://pastebin.com/tAACSy3M
It never has produced (even before any customization) code in script.sha.js. Things in scripts source folder just vanish in my build folder at grunt build task.
I don't understand the concat task executed with build. Where it is in the Gruntfile.js ? Because it execute things according to the terminal...
I found the solution after a good night to think...
I needed to learn how works grunt-usemin.
My HTML tag was incorrect because I forgotten to change <!-- build:js({.tmp,app}) scripts/scripts.js --> to <!-- build:js({.tmp,src}) scripts/scripts.js -->.
So, well, I think before the modification of this in my Gruntfile it worked... :/