variable line-display pager?

[Chip Camden]

Quoth Gary Kline on Saturday, 19 February 2011:
> On Sat, Feb 19, 2011 at 03:52:40PM -0800, Chip Camden wrote:
> > Quoth Gary Kline on Saturday, 19 February 2011:
> > > Need help findind a way of using existing unix utilities to diplay
> > > chunks of N lines of a text files.  Here N <= the number of lines in
> > > the file.
> > > 
> > > For instance, say that my xterm/console/"Konsole" is 80x53 lines.
> > > My text file is around 200 lines long and I want to use more or less
> > > or some GUI pager to display only 15 lines at one time.  Tapping the 
> > > space bar would display another 15 lines and so on until EOF.  Is
> > > there a way of doing with with flags of the existing /usr/bin/less
> > > or is there some other pager that I can build?
> > > 
> > > thanks,
> > > 
> > > gary
> > > 
> > > 
> > > 
> > > -- 
> > >  Gary Kline  kline at thought.org  http://www.thought.org  Public Service Unix
> > >            Journey Toward the Dawn, E-Book: http://www.thought.org
> > >           The 7.98a release of Jottings: http://jottings.thought.org
> > > 
> > > _______________________________________________
> > > freebsd-questions at freebsd.org mailing list
> > > http://lists.freebsd.org/mailman/listinfo/freebsd-questions
> > > To unsubscribe, send any mail to "freebsd-questions-unsubscribe at freebsd.org"
> > 
> > The -z option is supposed to do this:
> > 
> > less -z15 file.txt
> > 
> > But it appears to work only on the second and successive pages.
> 
> 
> 
> Oh.  So _that's_ why.  I tried less -m 15 [because the man pages
> sais z=N;  i just tried what you did with -z15.  Full page first
> time, 15 lines each spacebar thereafter.
> 
> Zank you, Sir Chip.. Anybody else?   I'm loathe to use anything gui,
> but here's  where I'll be happy w ith something GUI THat i can
> squeeze my "15" or small-n lines' worth into.  Can'y believe that
> there is nothing for all theses years....  I mean, geewhiz!
> Any idea where I Should look in ports or how to google this?
> 
> 
> gary
> 
> > 
> > -- 
> > Sterling (Chip) Camden | sterling at camdensoftware.com | 2048D/3A978E4F
> > http://chipsquips.com  | http://camdensoftware.com   | http://chipstips.com
> 
> 
> 
> -- 
>  Gary Kline  kline at thought.org  http://www.thought.org  Public Service Unix
>            Journey Toward the Dawn, E-Book: http://www.thought.org
>           The 7.98a release of Jottings: http://jottings.thought.org
> 
> _______________________________________________
> freebsd-questions at freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-questions
> To unsubscribe, send any mail to "freebsd-questions-unsubscribe at freebsd.org"

Is this sort of what you're looking for?

#!/usr/bin/env ruby
require 'optparse'

pagesize = 15

optparse = OptionParser.new do |opts|
  opts.banner = 'usage: npg [-n pagesize] file...'

  opts.on('-n', '--numlines pagesize', 'Specify page size in number of lines') do |n|
    pagesize = n
  end

end

begin
  optparse.parse!
rescue OptionParser::InvalidOption, OptionParser::MissingArgument => e
  puts e
  puts optparse
  exit 1
end

loop do
  pagesize.times do
    if line = gets
      puts line
    else
      exit
    end
  end
  print "More..."
  STDIN.getc
end

-- 
Sterling (Chip) Camden | sterling at camdensoftware.com | 2048D/3A978E4F
http://chipsquips.com  | http://camdensoftware.com   | http://chipstips.com
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