#! /usr/bin/perl -w

 # Script to take the output of nroff -man and remove all the backspacing and

 # the page footers and the screen commands etc so that it is more usefully

 # readable online. In fact, in the latest nroff, intermediate footers don't

 # seem to be generated any more.

 $blankcount = 0;

 $lastwascut = 0;

 $firstheader = 1;

 # Input on STDIN; output to STDOUT.

 while (<STDIN>)

   {

   s/\x1b\[\d+m//g;   # Remove screen controls "ESC [ number m"

   s/.\x8//g;         # Remove "char, backspace"

   # Handle header lines. Retain only the first one we encounter, but remove

   # the blank line that follows. Any others (e.g. at end of document) and the

   # following blank line are dropped.

   if (/^PCRE(\w*)\(([13])\)\s+PCRE\1\(\2\)$/)

     {

     if ($firstheader)

       {

       $firstheader = 0;

       print;

       $lastprinted = $_;

       $lastwascut = 0;

       }

     $_=<STDIN>;       # Remove a blank that follows

     next;

     }

   # Count runs of empty lines

   if (/^\s*$/)

     {

     $blankcount++;

     $lastwascut = 0;

     next;

     }

   # If a chunk of lines has been cut out (page footer) and the next line

   # has a different indentation, put back one blank line.

   if ($lastwascut && $blankcount < 1 && defined($lastprinted))

     {

     ($a) = $lastprinted =~ /^(\s*)/;

     ($b) = $_ =~ /^(\s*)/;

     $blankcount++ if ($a ne $b);

     }

   # We get here only when we have a non-blank line in hand. If it was preceded

   # by 3 or more blank lines, read the next 3 lines and see if they are blank.

   # If so, remove all 7 lines, and remember that we have just done a cut.

   if ($blankcount >= 3)

     {

     for ($i = 0; $i < 3; $i++)

       {

       $next[$i] = <STDIN>;

       $next[$i] = "" if !defined $next[$i];

       $next[$i] =~ s/\x1b\[\d+m//g;   # Remove screen controls "ESC [ number m"

       $next[$i] =~ s/.\x8//g;         # Remove "char, backspace"

       }

     # Cut out chunks of the form <3 blanks><non-blank><3 blanks>

     if ($next[0] =~ /^\s*$/ &&

         $next[1] =~ /^\s*$/ &&

         $next[2] =~ /^\s*$/)

       {

       $blankcount -= 3;

       $lastwascut = 1;

       }

     # Otherwise output the saved blanks, the current, and the next three

     # lines. Remember the last printed line.

     else

       {

       for ($i = 0; $i < $blankcount; $i++) { print "\n"; }

       print;

       for ($i = 0; $i < 3; $i++)

         {

         $next[$i] =~ s/.\x8//g;

         print $next[$i];

         $lastprinted = $_;

         }

       $lastwascut = 0;

       $blankcount = 0;

       }

     }

   # This non-blank line is not preceded by 3 or more blank lines. Output

   # any blanks there are, and the line. Remember it. Force two blank lines

   # before headings.

   else

     {

     $blankcount = 2 if /^\S/ && !/^Last updated/ && !/^Copyright/ &&

       defined($lastprinted);

     for ($i = 0; $i < $blankcount; $i++) { print "\n"; }

     print;

     $lastprinted = $_;

     $lastwascut = 0;

     $blankcount = 0;

     }

   }

 # End