From e5de0d457a42bd4f6e90f3b95a735b51330cc1b2 Mon Sep 17 00:00:00 2001
From: aiju <devnull@localhost>
Date: Sat, 25 Feb 2017 00:56:26 +0100
Subject: [PATCH] add redact(1)

---
 rc/bin/redact | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)
 create mode 100755 rc/bin/redact

diff --git a/rc/bin/redact b/rc/bin/redact
new file mode 100755
index 000000000..34206fa2e
--- /dev/null
+++ b/rc/bin/redact
@@ -0,0 +1,36 @@
+#!/bin/rc
+rfork e
+switch($#*){
+case 0
+	n=1
+case 1
+	n = $1
+case *
+	echo usage: $0 [n] >[1=2]
+	exit usage
+}
+ifs='
+'
+p=`{echo -n $prompt(1) | sed 's/[.*+?[\]()|\^$\/\\]/\\&/g'}
+awk '
+	BEGIN {
+		n='^$n^' + 1;
+		for(i = 0; i < n; i++)
+			a[i] = 0;
+	}
+	/^'^$p^'/ {
+		for(i = 0; i < n-1; i++)
+			a[i] = a[i+1];
+		a[n-1] = 0;
+	}
+	{
+		a[n-1] += length($0) + 1;
+	}
+	END {
+		s = 0;
+		for(i = 0; i < n; i++)
+			s += a[i];
+		for(i = 0; i < s; i++)
+			printf("\b");
+	}
+' /dev/text