bin/hi8: highlight 8-bit chars; -g for "grep" mode: show only lines with 8-bit

This is useful for cleaning files from 8-bit contamination obtained
through copy & paste, etc.

bin/hi8

@@ -0,0 +1,28 @@
+#!/usr/bin/perl
+sub usage
+{
+	print STDERR "usage: $0 [-g] [file ...]\n";
+	exit(1);
+}
+
+if ($ARGV[0] eq "-g") {
+	$grep = 1;
+	shift @ARGV;
+}
+&usage if $ARGV[0] =~ /^-/;
+
+while (<>) {
+	@c = unpack "C*";
+	for (@c) {
+		if ($_ == 10) {
+			print "$s\n" if $found || !$grep;
+			$found = 0;
+			undef $s;
+		} elsif ($_ < 0x80) {
+			$s .= pack("c", $_);
+		} else {
+			$s .= sprintf("\e[7m%02x\e[0m", $_);
+			$found = 1;
+		}
+	}
+}