diffin

#!/usr/bin/perl
#
# diff two or more buffers
# split buffers with an empty line (\n) or end STDIN multiple times (ctrl+d per buffer)
# -samy kamkar 2020/11/08
# https://samy.pl

use strict;
my $FILE = "/tmp/.diff.buf.";
my $DIFF = 'colordiff';
my @OPTS = qw/-btwur/;
my @buf;

# read in buffers until we have an empty one
do
{
  push @buf, join "", <STDIN>;
  print STDERR "read in buffer\r";
} while $buf[-1] ne "";

print "-" x 60, "\n";

# last is empty
pop @buf;

# if we only have one, treat empty lines as delimmeters
splice(@buf, 0, 1, split(/\n\n/, $buf[0])) if @buf == 1;

# last buff is empty
for my $i (1 .. @buf)
{
  open(OUT, ">$FILE$i");
  print OUT $buf[$i-1];
  close(OUT);

  system($DIFF, @OPTS, $FILE . ($i-1), $FILE . $i) if $i != 1;
}