This text comes from The Book of Scottish Song, edited by Alexander Whitelaw, a historical songbook transcribed on Wikisource and reproduced from the pinned revision linked below.
When first my brave Johnnie lad
Came to this town,
He had a blue bonnet
That wanted the crown;
But now he has gotten
A hat and a feather,—
Hey, brave Johnnie lad,
Cock up your beaver!
Cock up your beaver,
And cock it fu' sprush,
We'll over the border
And gi'e them a brush;
There's somebody there
We'll teach better behaviour—
Hey, brave Johnnie lad,
Cock up your beaver!