launch one jasmine test with grunt and karma?

I have a big web project with many javascript Jasmine unit tests.

In that web project, i use grunt, karma and jasmine.

Is there any way to launch only one test javascript with grunt with a command line ?

Launching all tests is long, so how to do that without modify my gruntfile.js or my karma-unit.conf.js ??

I tried the following command, but it is more a hack than a real solution :

karma run -- --grep=filteredtestexpr