#!/usr/local/bin/perl -s
#
# condense.pl
#
# Remove redundant empty lines

# Run condense.pl -h to see the options
#
# Last modified:        8/7/96
# Author: Bekman Stas   <c0409532@techst02.technion.ac.il>
#                       <sbekman@iil.intel.com>

$0 =~ s/^.*\///;        # cut the basename of the command

# Diagnostic part...
if ($#ARGV<0 || $h) {
die "\n\tRemoves redundant empty lines
Usage: 
\t $0 file(s)  
options:
   -h  		you read me now
   -no_bak	Don't backup the original file
   -none	Don't leave one empty line between paragraphs
\n"
}

# Real program...

# Store the original files' modes (Must do! Because of open(Bla,">foo") )
foreach (@ARGV) {
$modes{$_}=(stat)[2];
}


while (<>){
    if ($ARGV ne $oldargv){
    	if (!$no_bak) {rename($ARGV, $ARGV . '.bak');}
    	open (ARGVOUT, ">$ARGV") || die("Can't open $ARGV[0]: $!\n"); 
    	select(ARGVOUT);
    	$oldargv= $ARGV;
    }
    if ($empty) {s/^\s*\n//; (!$none) && ($empty=0);} 
    if (/^\s*$/) {$empty=1;}	

} continue { 
	print;		# this prints to the original filename
}

close(ARGVOUT);
select(STDOUT);

# Restore the original files' modes (Must do! Because of open(Bla,">foo") )
foreach (keys %modes) {
chmod $modes{$_},$_;
}