Maybe that's just me, but "Giving `head`" has a certain connotation. Apart from that, IMHO it does not fit to write that "-1" tells _us_ that _we_ only want the first line of the file. That is how you would read a script somebody else wrote.

But in this particular case _we_ are writing this, so I would phrase that as: "Passing `head` the parameter `-1` tells it to output the first line of the file only;"