From 6aa1d08a1ca86f46a44ed7afe802dd638c793400 Mon Sep 17 00:00:00 2001
From: Binh Vo <binhvo@gmail.com>
Date: Fri, 3 Dec 2021 15:31:33 -0500
Subject: [PATCH 1/4] Change zstdless behavior to align with zless

---
 programs/zstdless | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/programs/zstdless b/programs/zstdless
index 893799e7d95..10e7695473e 100755
--- a/programs/zstdless
+++ b/programs/zstdless
@@ -1,2 +1,6 @@
 #!/bin/sh
-zstdcat "$@" | less
+
+# TODO: Address quirks and bugs tied to old versions of less, provide a mechanism to pass flags directly to zstd
+
+export LESSOPEN="|zstd -cdfq %s"
+less "$@"

From e59e72bb3d2143bfeedea3368d333b89b540a2e8 Mon Sep 17 00:00:00 2001
From: Binh Vo <binhvo@gmail.com>
Date: Wed, 19 Jan 2022 21:43:23 -0500
Subject: [PATCH 2/4] Add simple tests

---
 tests/playTests.sh | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/tests/playTests.sh b/tests/playTests.sh
index b7a3d88a817..5dcf0deb8f6 100755
--- a/tests/playTests.sh
+++ b/tests/playTests.sh
@@ -89,6 +89,7 @@ PRGDIR="$SCRIPT_DIR/../programs"
 TESTDIR="$SCRIPT_DIR/../tests"
 UNAME=$(uname)
 ZSTDGREP="$PRGDIR/zstdgrep"
+ZSTDLESS="$PRGDIR/zstdless"
 
 detectedTerminal=false
 if [ -t 0 ] && [ -t 1 ]
@@ -322,6 +323,15 @@ ZCAT=./zstdcat "$ZSTDGREP" 2>&1 "1234" tmp_grep_bad.zst && die "Should have fail
 ZCAT=./zstdcat "$ZSTDGREP" 2>&1 "1234" tmp_grep_bad.zst | grep "No such file or directory" || true
 rm -f tmp_grep*
 
+println "\n===> zstdless tests"
+rm -f tmp_less
+echo "1234" > tmp_less
+zstd -f tmp_less
+lines=$("$ZSTDLESS" 2>&1 tmp_less.zst | wc -l)
+test 1 -eq $lines
+"$ZSTDLESS" 2>&1 tmp_less_bad.zst | grep "No such file or directory" || true
+rm -f tmp_less*
+
 println "\n===>  --exclude-compressed flag"
 rm -rf precompressedFilterTestDir
 mkdir -p precompressedFilterTestDir

From c439f5df65a2d470bf46a0a0e907465deb9d43ac Mon Sep 17 00:00:00 2001
From: Binh Vo <binhvo@gmail.com>
Date: Fri, 21 Jan 2022 11:15:14 -0500
Subject: [PATCH 3/4] Additional test and restore reverted commit

---
 programs/zstdless  |  6 ++++--
 tests/playTests.sh | 10 +++++++---
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/programs/zstdless b/programs/zstdless
index 10e7695473e..17726a4f6e1 100755
--- a/programs/zstdless
+++ b/programs/zstdless
@@ -1,6 +1,8 @@
 #!/bin/sh
 
+zstd=${ZSTD:-zstd}
+
 # TODO: Address quirks and bugs tied to old versions of less, provide a mechanism to pass flags directly to zstd
 
-export LESSOPEN="|zstd -cdfq %s"
-less "$@"
+export LESSOPEN="|-${zstd} -cdfq %s"
+exec less "$@"
diff --git a/tests/playTests.sh b/tests/playTests.sh
index 5dcf0deb8f6..4bc6c3fb232 100755
--- a/tests/playTests.sh
+++ b/tests/playTests.sh
@@ -324,12 +324,16 @@ ZCAT=./zstdcat "$ZSTDGREP" 2>&1 "1234" tmp_grep_bad.zst | grep "No such file or
 rm -f tmp_grep*
 
 println "\n===> zstdless tests"
-rm -f tmp_less
+ln -sf "$ZSTD_BIN" zstd
+rm -f tmp_less*
 echo "1234" > tmp_less
 zstd -f tmp_less
-lines=$("$ZSTDLESS" 2>&1 tmp_less.zst | wc -l)
+lines=$(ZSTD=./zstd "$ZSTDLESS" 2>&1 tmp_less.zst | wc -l)
 test 1 -eq $lines
-"$ZSTDLESS" 2>&1 tmp_less_bad.zst | grep "No such file or directory" || true
+ZSTD=./zstd "$ZSTDLESS" -f tmp_less.zst > tmp_less_regenerated
+cat tmp_less_regenerated
+$DIFF tmp_less tmp_less_regenerated
+ZSTD=./zstd "$ZSTDLESS" 2>&1 tmp_less_bad.zst | grep "No such file or directory" || true
 rm -f tmp_less*
 
 println "\n===>  --exclude-compressed flag"

From 332db9d1edcf0427a226a26e852fa7b453939fb2 Mon Sep 17 00:00:00 2001
From: Binh Vo <binhvo@gmail.com>
Date: Fri, 21 Jan 2022 16:48:35 -0500
Subject: [PATCH 4/4] Test fixes

---
 tests/playTests.sh | 23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/tests/playTests.sh b/tests/playTests.sh
index 4bc6c3fb232..041deb1eb18 100755
--- a/tests/playTests.sh
+++ b/tests/playTests.sh
@@ -324,17 +324,18 @@ ZCAT=./zstdcat "$ZSTDGREP" 2>&1 "1234" tmp_grep_bad.zst | grep "No such file or
 rm -f tmp_grep*
 
 println "\n===> zstdless tests"
-ln -sf "$ZSTD_BIN" zstd
-rm -f tmp_less*
-echo "1234" > tmp_less
-zstd -f tmp_less
-lines=$(ZSTD=./zstd "$ZSTDLESS" 2>&1 tmp_less.zst | wc -l)
-test 1 -eq $lines
-ZSTD=./zstd "$ZSTDLESS" -f tmp_less.zst > tmp_less_regenerated
-cat tmp_less_regenerated
-$DIFF tmp_less tmp_less_regenerated
-ZSTD=./zstd "$ZSTDLESS" 2>&1 tmp_less_bad.zst | grep "No such file or directory" || true
-rm -f tmp_less*
+if [ -n "$(which less)" ]; then
+  ln -sf "$ZSTD_BIN" zstd
+  rm -f tmp_less*
+  echo "1234" > tmp_less
+  zstd -f tmp_less
+  lines=$(ZSTD=./zstd "$ZSTDLESS" 2>&1 tmp_less.zst | wc -l)
+  test 1 -eq $lines
+  ZSTD=./zstd "$ZSTDLESS" -f tmp_less.zst > tmp_less_regenerated
+  $DIFF tmp_less tmp_less_regenerated
+  ZSTD=./zstd "$ZSTDLESS" 2>&1 tmp_less_bad.zst | grep "No such file or directory" || die
+  rm -f tmp_less*
+fi
 
 println "\n===>  --exclude-compressed flag"
 rm -rf precompressedFilterTestDir