ssh doesn't let you specify a command precisely, as you have done, as a series of arguments to be passed to execvp on the remote host. Instead it concatenates all the arguments into a string and runs them through a remote shell. This stands out as a major design flaw in ssh in my opinion... it's a well-behaved unix tool in most ways, but when it comes time to specify a command it chose to use a single monolithic string instead of an argv, like it was designed for MSDOS or something!