I needed to paste a bunch of data to my browser to get it into a gist and didn’t want to copy and paste a page at a time. Install the ‘xsel’ package and you can use it to manipulate the clipboards.
ohai | xsel -b
This takes the output of the program and puts it on the ‘clipboard selection’ instead of the ‘primary selection’, which I needed to do to make firefox happy. You can also see the selections from the command prompt with ‘xsel -o’.