From 1d314b81aa5b0c4530638ffabd4e0edb52e5362c Mon Sep 17 00:00:00 2001
From: Jonathan Nieder <jrnieder@gmail.com>
Date: Sun, 9 Aug 2009 13:22:12 -0500
Subject: [PATCH] xzless: Support compressed standard input
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It can be somewhat confusing that

	less < some_file.txt

works fine, whereas

	xzless < some_file.txt.xz

does not.  Since version 429, ‘less’ allows a filter specified in
the LESSOPEN environment variable to preprocess its input even if
it comes from standard input, if $LESSOPEN begins with ‘|-’.  So
set $LESSOPEN to take advantage of this feature.

Check less’s version at runtime so xzless can continue to work
with older versions.
---
 src/scripts/xzless.in | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/scripts/xzless.in b/src/scripts/xzless.in
index 6639943a..a3da697c 100644
--- a/src/scripts/xzless.in
+++ b/src/scripts/xzless.in
@@ -46,7 +46,13 @@ if test "${LESSMETACHARS+set}" != set; then
 	LESSMETACHARS="$space$tab$nl'"';*?"()<>[|&^`#\$%=~'
 fi
 
-LESSOPEN="|$xz -cdfq -- %s"
+if test "$(less -V | { read ver && echo ${ver#less }; })" -ge 429; then
+	# less 429 or later: LESSOPEN pipe will be used on
+	# standard input if $LESSOPEN begins with |-.
+	LESSOPEN="|-$xz -cdfq -- %s"
+else
+	LESSOPEN="|$xz -cdfq -- %s"
+fi
 export LESSMETACHARS LESSOPEN
 
 exec less "$@"