That's missing some quotes; it's trying to set an environment variable called -g, which is an invalid identifier. Mine is
export PAGER=less LESS='-wiXz-2$j15' LESSBINFMT=. export PAGER=less LESS='-wiXz-2$j15' LESSBINFMT=.In addition to displaying ordinary text files, most can also display binary files as well as files with arbitrary ascii characters.