The System V version of has a -F option for folding lines that are too wide for the output page: the printer won't truncate them. If you print lots of random data and stuff that may have long lines and your pr doesn't have -F , try the fold command instead.
fold arbitrarily breaks lines that are too long, by default at 80 columns. Use - width where width is the desired column to fold at for some other breaking point.
I made an
alias prF 'fold \!^ | pr -h "\!^"'
alias prnF 'cat -n \!^ | fold | pr -h "\!^"'
To shorten lines by folding them after a word near the right-hand end (instead of at some particluar column), try.