b (browse) command for ed(1)
Beginning with the Eighth Edition, ed(1) had the following command.
Tue Oct 11 14:38:08 2016 - permalink -
This is from the Plan 9 ed man page.
Browse. Print a `page', normally 20 lines. The
optional `+' (default) or `-' specifies whether the
next or previous page is to be printed. The optional
pagesize is the number of lines in a page. The
optional `p', `n', or `l' causes printing in the speci-
fied format, initially `p'. Pagesize and format are
remembered between `b' commands. Dot is left at the
last line displayed.