This song, with its tune, is in Songs of the People by Sam Henry (Athens, GA: University of Georgia Press, 1990), page 23:

BELLAGHY FAIR

I went to the fair in Bellaghy.
I bought a wee swad of a pig.
I got it up in my arms
And danced 'The Swaggering Jig.'
Then it's hi! for the top o' the heather,
And hi! for the root of the sprig,
And hi! for the bonnie wee lassie
That danced 'The Swaggering Jig.'

As I went to the fair of Bellaghy,
I bought a wee slip o' a pig,
And as I was passing the poorhouse,
I whistled 'The Swaggering Jig.'
Then it's Hi! for the cups and the saucers,
And Hi! for the butter and bread;
And Hi! for the bonny wee lassie,
That danced 'The Swaggering Jig.'

As I being down by the Poorhouse,
I whistled so loud and so shrill,
I made all the fairies to tremble
That live near McCloughrim Hill,
Then it's hi! for the cups and the saucers,
And hi! for the butter and bread,
And hi! for the bonny wee lassie
That danced 'The Swaggering Jig.'