diff --git a/src/cmd/ksh93/tests/alias.sh b/src/cmd/ksh93/tests/alias.sh
index 2b3bc6196..084fdb1ab 100755
--- a/src/cmd/ksh93/tests/alias.sh
+++ b/src/cmd/ksh93/tests/alias.sh
@@ -28,14 +28,7 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.alias.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 
 alias foo='print hello'
 if	[[ $(foo) != hello ]]
diff --git a/src/cmd/ksh93/tests/append.sh b/src/cmd/ksh93/tests/append.sh
index 6afec5694..6617c36d2 100755
--- a/src/cmd/ksh93/tests/append.sh
+++ b/src/cmd/ksh93/tests/append.sh
@@ -27,6 +27,9 @@ alias err_exit='err_exit $LINENO'
 
 Command=${0##*/}
 integer Errors=0
+
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 {
 x=abc
 x+=def ;} 2> /dev/null
diff --git a/src/cmd/ksh93/tests/arith.sh b/src/cmd/ksh93/tests/arith.sh
index 0f9cb1703..e1aa91532 100755
--- a/src/cmd/ksh93/tests/arith.sh
+++ b/src/cmd/ksh93/tests/arith.sh
@@ -28,14 +28,7 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.arith.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 
 trap '' FPE # NOTE: osf.alpha requires this (no ieee math)
 
diff --git a/src/cmd/ksh93/tests/arrays.sh b/src/cmd/ksh93/tests/arrays.sh
index 201833aa1..a766bd37f 100755
--- a/src/cmd/ksh93/tests/arrays.sh
+++ b/src/cmd/ksh93/tests/arrays.sh
@@ -28,14 +28,7 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.arrays.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 
 function fun
 {
diff --git a/src/cmd/ksh93/tests/arrays2.sh b/src/cmd/ksh93/tests/arrays2.sh
index ff9e21f64..f3e208927 100755
--- a/src/cmd/ksh93/tests/arrays2.sh
+++ b/src/cmd/ksh93/tests/arrays2.sh
@@ -27,6 +27,9 @@ alias err_exit='err_exit $LINENO'
 
 Command=${0##*/}
 integer Errors=0
+
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 for	((i=0; i < 4; i++ ))
 do	for	((j=0; j < 5; j++ ))
 	do	a[i][j]=$i$j
diff --git a/src/cmd/ksh93/tests/attributes.sh b/src/cmd/ksh93/tests/attributes.sh
index 435657b5a..5090b66f9 100755
--- a/src/cmd/ksh93/tests/attributes.sh
+++ b/src/cmd/ksh93/tests/attributes.sh
@@ -28,14 +28,7 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.attributes.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 
 r=readonly u=Uppercase l=Lowercase i=22 i8=10 L=abc L5=def uL5=abcdef xi=20
 x=export t=tagged H=hostname LZ5=026 RZ5=026 Z5=123 lR5=ABcdef R5=def n=l
diff --git a/src/cmd/ksh93/tests/basic.sh b/src/cmd/ksh93/tests/basic.sh
index aae2995fe..515dfb28d 100755
--- a/src/cmd/ksh93/tests/basic.sh
+++ b/src/cmd/ksh93/tests/basic.sh
@@ -28,14 +28,8 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.basic.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 bincat=$(whence -p cat)
 binecho=$(whence -p echo)
 # make an external 'sleep' command that supports fractional seconds
diff --git a/src/cmd/ksh93/tests/bracket.sh b/src/cmd/ksh93/tests/bracket.sh
index 5b7745fe2..25e47a461 100755
--- a/src/cmd/ksh93/tests/bracket.sh
+++ b/src/cmd/ksh93/tests/bracket.sh
@@ -28,14 +28,7 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.bracket.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 
 null=''
 if	[[ ! -z $null ]]
diff --git a/src/cmd/ksh93/tests/builtins.sh b/src/cmd/ksh93/tests/builtins.sh
index 43b23fb82..470644be4 100755
--- a/src/cmd/ksh93/tests/builtins.sh
+++ b/src/cmd/ksh93/tests/builtins.sh
@@ -28,14 +28,8 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.builtins.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 bincat=$(whence -p cat)
 
 # test shell builtin commands
@@ -194,7 +188,7 @@ mkdir -p $tmp/a/b/c 2>/dev/null || err_exit  "mkdir -p failed"
 $SHELL -c "cd $tmp/a/b; cd c" 2>/dev/null || err_exit "initial script relative cd fails"
 
 trap 'print TERM' TERM
-exp=$'trap -- \'print TERM\' TERM\ntrap -- \'cd / && rm -rf "$tmp"\' EXIT'
+exp="trap -- 'print TERM' TERM"
 got=$(trap)
 [[ $got == $exp ]] || err_exit "\$(trap) failed -- expected \"$exp\", got \"$got\""
 exp='print TERM'
diff --git a/src/cmd/ksh93/tests/case.sh b/src/cmd/ksh93/tests/case.sh
index 7fe01ea88..500fc6bc5 100755
--- a/src/cmd/ksh93/tests/case.sh
+++ b/src/cmd/ksh93/tests/case.sh
@@ -28,6 +28,8 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 bar=foo2
 bam=foo[3]
 for i in foo1 foo2 foo3 foo4 foo5 foo6
diff --git a/src/cmd/ksh93/tests/comvar.sh b/src/cmd/ksh93/tests/comvar.sh
index e705238b4..387cf1358 100755
--- a/src/cmd/ksh93/tests/comvar.sh
+++ b/src/cmd/ksh93/tests/comvar.sh
@@ -25,14 +25,10 @@ function err_exit
 }
 alias err_exit='err_exit $LINENO'
 
-tmp=$(
-    d=${TMPDIR:-/tmp}/ksh93.comvar.$$.${RANDOM:-0}
-    mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-    err\_exit $LINENO 'mkdir failed'
-    exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+Command=${0##*/}
+integer Errors=0
+
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 
 #test for compound variables
 Command=${0##*/}
diff --git a/src/cmd/ksh93/tests/comvario.sh b/src/cmd/ksh93/tests/comvario.sh
index 2069dd5aa..b4be1bd4d 100755
--- a/src/cmd/ksh93/tests/comvario.sh
+++ b/src/cmd/ksh93/tests/comvario.sh
@@ -46,6 +46,11 @@ function err_exit
 }
 alias err_exit='err_exit $LINENO'
 
+Command=${0##*/}
+integer Errors=0
+
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 # "nounset" disabled for now
 #set -o nounset
 Command=${0##*/}
diff --git a/src/cmd/ksh93/tests/coprocess.sh b/src/cmd/ksh93/tests/coprocess.sh
index 4e2d0b730..95f85cca6 100755
--- a/src/cmd/ksh93/tests/coprocess.sh
+++ b/src/cmd/ksh93/tests/coprocess.sh
@@ -29,14 +29,7 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.coprocess.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 
 if	[[ -d /cygdrive ]]
 then	err_exit cygwin detected - coprocess tests disabled - enable at the risk of wedging your system
diff --git a/src/cmd/ksh93/tests/cubetype.sh b/src/cmd/ksh93/tests/cubetype.sh
index dbe4e8bef..e8a2282c7 100755
--- a/src/cmd/ksh93/tests/cubetype.sh
+++ b/src/cmd/ksh93/tests/cubetype.sh
@@ -29,6 +29,8 @@ Command=${0##*/}
 integer Errors=0
 integer n=2
 
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 typeset -T Box_t=(
 	float -h 'height in inches' x=2
 	float -h 'width in inches' y=4
diff --git a/src/cmd/ksh93/tests/enum.sh b/src/cmd/ksh93/tests/enum.sh
index 4f9ff834b..5487c37e7 100755
--- a/src/cmd/ksh93/tests/enum.sh
+++ b/src/cmd/ksh93/tests/enum.sh
@@ -27,6 +27,9 @@ alias err_exit='err_exit $LINENO'
 
 Command=${0##*/}
 integer Errors=0
+
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 enum Color_t=(red green blue orange yellow)
 enum -i Sex_t=(Male Female)
 for ((i=0; i < 1000; i++))
diff --git a/src/cmd/ksh93/tests/exit.sh b/src/cmd/ksh93/tests/exit.sh
index aaf822eb0..166f2010c 100755
--- a/src/cmd/ksh93/tests/exit.sh
+++ b/src/cmd/ksh93/tests/exit.sh
@@ -28,14 +28,7 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.exit.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 
 function abspath
 {
diff --git a/src/cmd/ksh93/tests/expand.sh b/src/cmd/ksh93/tests/expand.sh
index 123698cd5..c568e457a 100755
--- a/src/cmd/ksh93/tests/expand.sh
+++ b/src/cmd/ksh93/tests/expand.sh
@@ -27,6 +27,8 @@ function err_exit
 integer Errors=0
 Command=${0##*/}
 
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 # {...} expansion tests -- ignore if not supported
 
 [[ $(print a{0,1}z) == "a0z a1z" ]] || exit 0
diff --git a/src/cmd/ksh93/tests/functions.sh b/src/cmd/ksh93/tests/functions.sh
index e5dbd7173..7178bbf97 100755
--- a/src/cmd/ksh93/tests/functions.sh
+++ b/src/cmd/ksh93/tests/functions.sh
@@ -27,20 +27,15 @@ alias err_exit='err_exit $LINENO'
 
 integer Errors=0
 Command=${0##*/}
+
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 compiled=''
 read -n4 c < $0 2> /dev/null
 [[ $c == *$'\ck'* ]] && compiled=1
 
 ulimit -c 0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.functions.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
 binecho=$(whence -p echo)
 
 integer foo=33
diff --git a/src/cmd/ksh93/tests/glob.sh b/src/cmd/ksh93/tests/glob.sh
index a0ad8b196..8dec730ae 100755
--- a/src/cmd/ksh93/tests/glob.sh
+++ b/src/cmd/ksh93/tests/glob.sh
@@ -27,14 +27,7 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer aware=0 contrary=0 Errors=0 ignorant=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.glob.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 
 function test_glob
 {
diff --git a/src/cmd/ksh93/tests/grep.sh b/src/cmd/ksh93/tests/grep.sh
index a0b80ccf7..c07b97813 100755
--- a/src/cmd/ksh93/tests/grep.sh
+++ b/src/cmd/ksh93/tests/grep.sh
@@ -28,14 +28,7 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.grep.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 
 function grep
 {
diff --git a/src/cmd/ksh93/tests/heredoc.sh b/src/cmd/ksh93/tests/heredoc.sh
index 2d9e21d5b..1cabd44e3 100755
--- a/src/cmd/ksh93/tests/heredoc.sh
+++ b/src/cmd/ksh93/tests/heredoc.sh
@@ -28,14 +28,8 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.heredoc.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 bincat=$(whence -p cat)
 
 f=$tmp/here1
diff --git a/src/cmd/ksh93/tests/io.sh b/src/cmd/ksh93/tests/io.sh
index 51eba6ce0..fb86b45cd 100755
--- a/src/cmd/ksh93/tests/io.sh
+++ b/src/cmd/ksh93/tests/io.sh
@@ -28,14 +28,7 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.io.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 
 unset HISTFILE
 
diff --git a/src/cmd/ksh93/tests/leaks.sh b/src/cmd/ksh93/tests/leaks.sh
index a1c5cfbad..54b0f711e 100755
--- a/src/cmd/ksh93/tests/leaks.sh
+++ b/src/cmd/ksh93/tests/leaks.sh
@@ -29,6 +29,8 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 # Get the current amount of memory usage
 function getmem
 {
diff --git a/src/cmd/ksh93/tests/locale.sh b/src/cmd/ksh93/tests/locale.sh
index 26dc9c20e..f8aeb7703 100755
--- a/src/cmd/ksh93/tests/locale.sh
+++ b/src/cmd/ksh93/tests/locale.sh
@@ -28,17 +28,10 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-unset LANG ${!LC_*}
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+CDPATH= cd -P -- "$tmp" || exit
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.locale.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
-cd $tmp || exit
+unset LANG ${!LC_*}
 
 a=$($SHELL -c '/' 2>&1 | sed -e "s,.*: *,," -e "s, *\[.*,,")
 b=$($SHELL -c '(LC_ALL=debug / 2>/dev/null); /' 2>&1 | sed -e "s,.*: *,," -e "s, *\[.*,,")
diff --git a/src/cmd/ksh93/tests/math.sh b/src/cmd/ksh93/tests/math.sh
index 76cb518c9..4c34d14e2 100755
--- a/src/cmd/ksh93/tests/math.sh
+++ b/src/cmd/ksh93/tests/math.sh
@@ -25,25 +25,14 @@ function err_exit
 }
 alias err_exit='err_exit $LINENO'
 
-set -o nounset
 Command=${0##*/}
 integer Errors=0
 
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+CDPATH= cd -P -- "$tmp" || exit
+
 set -o nounset
 
-typeset tmp
-
-# create temporary test directory
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.math.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
-cd $tmp || exit
-
 function test_arithmetric_expression_accesss_array_element_through_nameref
 {
         compound out=( typeset stdout stderr ; integer res )
diff --git a/src/cmd/ksh93/tests/nameref.sh b/src/cmd/ksh93/tests/nameref.sh
index abf46829c..36d4ef914 100755
--- a/src/cmd/ksh93/tests/nameref.sh
+++ b/src/cmd/ksh93/tests/nameref.sh
@@ -28,14 +28,7 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.nameref.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 
 function checkref
 {
diff --git a/src/cmd/ksh93/tests/namespace.sh b/src/cmd/ksh93/tests/namespace.sh
index 46b98cd15..99b6843bb 100755
--- a/src/cmd/ksh93/tests/namespace.sh
+++ b/src/cmd/ksh93/tests/namespace.sh
@@ -28,14 +28,7 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.namespace.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 
 foo=abc
 typeset -C bar=(x=3 y=4 t=7)
diff --git a/src/cmd/ksh93/tests/options.sh b/src/cmd/ksh93/tests/options.sh
index 5093f7d6d..28eb7df43 100755
--- a/src/cmd/ksh93/tests/options.sh
+++ b/src/cmd/ksh93/tests/options.sh
@@ -28,19 +28,13 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 unset HISTFILE
 export LC_ALL=C ENV=/./dev/null
 
 ulimit -c 0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.options.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
 bincat=$(whence -p cat)
 
 if	[[ $( ${SHELL-ksh} -s hello<<-\!
diff --git a/src/cmd/ksh93/tests/path.sh b/src/cmd/ksh93/tests/path.sh
index 9725c74e3..295f5706c 100755
--- a/src/cmd/ksh93/tests/path.sh
+++ b/src/cmd/ksh93/tests/path.sh
@@ -28,16 +28,9 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.path.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+CDPATH= cd -P -- "$tmp" || exit
 
-cd $tmp || exit
 type /xxxxxx > out1 2> out2
 [[ -s out1 ]] && err_exit 'type should not write on stdout for not found case'
 [[ -s out2 ]] || err_exit 'type should write on stderr for not found case'
diff --git a/src/cmd/ksh93/tests/pointtype.sh b/src/cmd/ksh93/tests/pointtype.sh
index b0a533319..dad634f12 100755
--- a/src/cmd/ksh93/tests/pointtype.sh
+++ b/src/cmd/ksh93/tests/pointtype.sh
@@ -28,6 +28,8 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 typeset -T Pt_t=(
 	float x=1
 	float y=0
diff --git a/src/cmd/ksh93/tests/pty.sh b/src/cmd/ksh93/tests/pty.sh
index bed9564ef..e588226cc 100755
--- a/src/cmd/ksh93/tests/pty.sh
+++ b/src/cmd/ksh93/tests/pty.sh
@@ -41,7 +41,8 @@ alias err_exit='err_exit $lineno'
 Command=${0##*/}
 integer Errors=0 lineno=1
 
-whence -q pty || { lineno=$LINENO; err_exit "pty command not found -- tests skipped"; exit 0; }
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+whence -q pty || { lineno=$LINENO; err\_exit "$LINENO" "pty command not found -- tests skipped"; exit 0; }
 
 bintrue=$(whence -p true)
 
diff --git a/src/cmd/ksh93/tests/quoting.sh b/src/cmd/ksh93/tests/quoting.sh
index 60fbf3a0b..c1651df9f 100755
--- a/src/cmd/ksh93/tests/quoting.sh
+++ b/src/cmd/ksh93/tests/quoting.sh
@@ -27,6 +27,9 @@ alias err_exit='err_exit $LINENO'
 
 Command=${0##*/}
 integer Errors=0
+
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 binecho=$(whence -p echo)
 
 if	[[ 'hi there' != "hi there" ]]
diff --git a/src/cmd/ksh93/tests/quoting2.sh b/src/cmd/ksh93/tests/quoting2.sh
index bc7380d06..0ffcb4fae 100755
--- a/src/cmd/ksh93/tests/quoting2.sh
+++ b/src/cmd/ksh93/tests/quoting2.sh
@@ -27,6 +27,9 @@ alias err_exit='err_exit $LINENO'
 
 Command=${0##*/}
 integer Errors=0
+
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 set -o noglob
 if	[[ 'hi there' != "hi there" ]]
 then	err_exit "single quotes not the same as double quotes"
diff --git a/src/cmd/ksh93/tests/readcsv.sh b/src/cmd/ksh93/tests/readcsv.sh
index 97cea24e9..a01e782bc 100755
--- a/src/cmd/ksh93/tests/readcsv.sh
+++ b/src/cmd/ksh93/tests/readcsv.sh
@@ -28,14 +28,7 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.readcsv.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 	
 tmp1=$tmp/tmp1.csv
 tmp2=$tmp/tmp2.csv
diff --git a/src/cmd/ksh93/tests/recttype.sh b/src/cmd/ksh93/tests/recttype.sh
index 9f41d9266..e62a7171c 100755
--- a/src/cmd/ksh93/tests/recttype.sh
+++ b/src/cmd/ksh93/tests/recttype.sh
@@ -28,6 +28,8 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 typeset -T Pt_t=(
 	float x=1
 	float y=0
diff --git a/src/cmd/ksh93/tests/restricted.sh b/src/cmd/ksh93/tests/restricted.sh
index a52c51731..b77ecdbea 100755
--- a/src/cmd/ksh93/tests/restricted.sh
+++ b/src/cmd/ksh93/tests/restricted.sh
@@ -28,14 +28,8 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.restricted.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 binecho=$(whence -p echo)
 
 # test restricted shell
diff --git a/src/cmd/ksh93/tests/return.sh b/src/cmd/ksh93/tests/return.sh
index 65a7be536..b492409db 100755
--- a/src/cmd/ksh93/tests/return.sh
+++ b/src/cmd/ksh93/tests/return.sh
@@ -30,14 +30,7 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.return.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 
 unset HISTFILE
 
diff --git a/src/cmd/ksh93/tests/select.sh b/src/cmd/ksh93/tests/select.sh
index 6a465507f..01051b9bf 100755
--- a/src/cmd/ksh93/tests/select.sh
+++ b/src/cmd/ksh93/tests/select.sh
@@ -28,14 +28,7 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.select.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 
 PS3='ABC '
 
diff --git a/src/cmd/ksh93/tests/shtests b/src/cmd/ksh93/tests/shtests
index 926db479f..52aa0c8d9 100755
--- a/src/cmd/ksh93/tests/shtests
+++ b/src/cmd/ksh93/tests/shtests
@@ -10,7 +10,7 @@ valgrindflags='--xml=yes --log-file=/dev/null --track-origins=yes --read-var-inf
 
 USAGE=$'
 [-s8?
-@(#)$Id: shtests (AT&T Research/ksh93) 2020-06-23 $
+@(#)$Id: shtests (AT&T Research/ksh93) 2020-07-04 $
 ]
 '$USAGE_LICENSE$'
 [+NAME?shtests - ksh regression test harness]
@@ -31,6 +31,7 @@ USAGE=$'
     }
 [c:compile?Run test scripts using \bshcomp\b(1).]
 [d:debug?Enable \bshtests\b execution trace.]
+[k:keep?Keep temporary files after test run; shtests will report the location.]
 [l:locale?Disable \b--utf8\b and run the \b--posix\b and \b--compile\b
     tests, if enabled, in the locale of the caller. This may cause invalid
     regressions, especially for locales where \b.\b is not the radix
@@ -170,7 +171,7 @@ export ENV=/./dev/null
 trap + PIPE # unadvertized -- set SIGPIPE to SIG_DFL #
 
 integer compile=-1 posix=-1 utf8=-1
-integer debug=0 locale=0 time=1
+integer debug=0 keep=0 locale=0 time=1
 typeset vmalloc_options=abort trace= valgrind=
 vmalloc_options= #XXX# until multi-region vmalloc trace fixed #XXX#
 
@@ -183,6 +184,9 @@ do	case $OPT in
 		;;
 	d)	debug=$OPTARG
 		;;
+	k)	keep=$OPTARG
+		echo "[DEBUG] keep == [$keep]" >&2
+		;;
 	l)	locale=$OPTARG
 		;;
 	p)	posix=$OPTARG
@@ -282,7 +286,10 @@ tmp=$(
 	echo 'mkdir failed' >&2
 	exit 1
 }
-trap 'cd / && rm -rf "$tmp"' EXIT
+if	(( keep ))
+then	trap 'printf "\nTemporary files left in: %s\n" "$tmp"' EXIT
+else	trap 'cd / && rm -rf "$tmp"' EXIT
+fi
 
 if	(( compile ))
 then	if	whence $SHCOMP > /dev/null
@@ -329,14 +336,22 @@ do	[[ $i == *.sh ]] || i+='.sh'
 		[[ $utf8 == 0 || $i == $setslocale ]] || locales+=" C.UTF-8"
 		for lang in $locales
 		do	o=$u
+			tmp_s=$tmp/$u.$lang
+			mkdir -m700 "$tmp_s" || exit
 			if	[[ $lang == C ]]
 			then	lang=
 			else	o="$o($lang)"
 				lang=LANG=$lang
 			fi
 			echo test $o begins ${time:+"at $(date +%Y-%m-%d+%H:%M:%S)"}
-			eval $lang \$valgrind \$SHELL \$trace \$i
+			(
+				export ${lang:+"$lang"} "tmp=$tmp_s"
+				$valgrind $SHELL $trace $i
+			)
 			e=$?
+			if	(( !keep ))
+			then	rm -rf "$tmp_s"
+			fi
 			if	[[ $valgrind ]]
 			then	valxml $valxml
 				(( e += $? ))
@@ -361,8 +376,10 @@ do	[[ $i == *.sh ]] || i+='.sh'
 	then	c=$tmp/shcomp-$u.ksh
 		o="$u(shcomp)"
 		echo test $o begins ${time:+"at $(date +%Y-%m-%d+%H:%M:%S)"}
+		tmp_s=$tmp/$u.shcomp
+		mkdir -m700 "$tmp_s" || exit
 		if	$SHCOMP $i > $c
-		then	if	$valgrind $SHELL $trace $c
+		then	if	tmp=$tmp_s $valgrind $SHELL $trace $c
 			then	echo test $o passed ${time:+"at $(date +%Y-%m-%d+%H:%M:%S)"} "[ $t $T 0 errors ]"
 			else	e=$?
 				if	(( e > 128 && ++total_e ))
@@ -381,6 +398,9 @@ do	[[ $i == *.sh ]] || i+='.sh'
 			(( ++total_e ))
 			echo test $o failed to compile ${time:+"at $(date +%Y-%m-%d+%H:%M:%S)"} with exit code $e "[ 1 test 1 error ]"
 		fi
+		if	(( !keep ))
+		then	rm -rf "$tmp_s" "$c"
+		fi
 		if	[[ $i == $timesensitive ]]
 		then	VMALLOC_OPTIONS=$vmalloc_options
 		fi
diff --git a/src/cmd/ksh93/tests/sigchld.sh b/src/cmd/ksh93/tests/sigchld.sh
index 47c5bf8fc..3cd9e804e 100755
--- a/src/cmd/ksh93/tests/sigchld.sh
+++ b/src/cmd/ksh93/tests/sigchld.sh
@@ -23,20 +23,15 @@ function err_exit
 	print -u2 -r ${Command}[$1]: "${@:2}"
 	(( Errors+=1 ))
 }
-
 alias err_exit='err_exit $LINENO'
 
-float DELAY=${1:-0.02}
-integer FOREGROUND=10 BACKGROUND=2 Errors=0
+Command=${0##*/}
+integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.sigchld.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
+float DELAY=${1:-0.02}
+integer FOREGROUND=10 BACKGROUND=2
 
 s=$($SHELL -c '
 integer i foreground=0 background=0
diff --git a/src/cmd/ksh93/tests/signal.sh b/src/cmd/ksh93/tests/signal.sh
index 9c0b86223..5e7f4b9dd 100755
--- a/src/cmd/ksh93/tests/signal.sh
+++ b/src/cmd/ksh93/tests/signal.sh
@@ -28,16 +28,8 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.signal.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
-
-cd $tmp || err_exit "cd $tmp failed"
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+CDPATH= cd -P -- "$tmp" || exit
 
 unset n s t
 typeset -A SIG
diff --git a/src/cmd/ksh93/tests/statics.sh b/src/cmd/ksh93/tests/statics.sh
index 2168f156c..b3e989b56 100755
--- a/src/cmd/ksh93/tests/statics.sh
+++ b/src/cmd/ksh93/tests/statics.sh
@@ -27,14 +27,14 @@ function err_exit
 	print -u2 -r ${Command}[$1]: "${@:2}"
 	(( Errors < 127 && Errors++ ))
 }
-
 alias err_exit='err_exit $LINENO'
 
-set -o nounset
 Command=${0##*/}
 integer Errors=0
 
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 
+set -o nounset
 
 typeset -T test_t=(
 	typeset name
diff --git a/src/cmd/ksh93/tests/subshell.sh b/src/cmd/ksh93/tests/subshell.sh
index d7b67a97d..edd11b3ba 100755
--- a/src/cmd/ksh93/tests/subshell.sh
+++ b/src/cmd/ksh93/tests/subshell.sh
@@ -29,14 +29,7 @@ Command=${0##*/}
 integer Errors=0
 typeset -F SECONDS  # for fractional seconds in PS4
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.subshell.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 
 builtin getconf
 bincat=$(PATH=$(getconf PATH) whence -p cat)
diff --git a/src/cmd/ksh93/tests/substring.sh b/src/cmd/ksh93/tests/substring.sh
index b74c18143..e4b970ff3 100755
--- a/src/cmd/ksh93/tests/substring.sh
+++ b/src/cmd/ksh93/tests/substring.sh
@@ -27,6 +27,9 @@ alias err_exit='err_exit $LINENO'
 
 Command=${0##*/}
 integer Errors=0
+
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 tmpPS4='+ [temp_PS4|L$LINENO|e$?] '  # used to avoid interference to ${.sh.match} from $PS4 set by shtests
 
 integer j=4
diff --git a/src/cmd/ksh93/tests/tilde.sh b/src/cmd/ksh93/tests/tilde.sh
index 7b2e645c0..affb117cd 100755
--- a/src/cmd/ksh93/tests/tilde.sh
+++ b/src/cmd/ksh93/tests/tilde.sh
@@ -28,14 +28,7 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.tilde.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 
 if	$SHELL -c '[[ ~root == /* ]]'
 then	x=$(print -r -- ~root)
diff --git a/src/cmd/ksh93/tests/timetype.sh b/src/cmd/ksh93/tests/timetype.sh
index 16453c47e..d8a58f356 100755
--- a/src/cmd/ksh93/tests/timetype.sh
+++ b/src/cmd/ksh93/tests/timetype.sh
@@ -28,6 +28,8 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 typeset -T Time_t=(
 	integer .=-1
 	_='%F+%H:%M'
diff --git a/src/cmd/ksh93/tests/treemove.sh b/src/cmd/ksh93/tests/treemove.sh
index 8e293c082..f5ef434f9 100755
--- a/src/cmd/ksh93/tests/treemove.sh
+++ b/src/cmd/ksh93/tests/treemove.sh
@@ -59,11 +59,13 @@ function err_exit
 	print -u2 -r ${Command}[$1]: "${@:2}"
 	(( Errors+=1 ))
 }
-
 alias err_exit='err_exit $LINENO'
 
+Command=${0##*/}
 integer Errors=0
 
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 ## test start
 typeset -C tree1 tree2
 
diff --git a/src/cmd/ksh93/tests/types.sh b/src/cmd/ksh93/tests/types.sh
index 220cccdb8..95135abd8 100755
--- a/src/cmd/ksh93/tests/types.sh
+++ b/src/cmd/ksh93/tests/types.sh
@@ -28,14 +28,7 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.types.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 
 integer n=2
 
diff --git a/src/cmd/ksh93/tests/variables.sh b/src/cmd/ksh93/tests/variables.sh
index c9bb3fc54..60554282d 100755
--- a/src/cmd/ksh93/tests/variables.sh
+++ b/src/cmd/ksh93/tests/variables.sh
@@ -28,14 +28,7 @@ alias err_exit='err_exit $LINENO'
 Command=${0##*/}
 integer Errors=0
 
-tmp=$(
-	d=${TMPDIR:-/tmp}/ksh93.variables.$$.${RANDOM:-0}
-	mkdir -m700 -- "$d" && CDPATH= cd -P -- "$d" && pwd
-) || {
-	err\_exit $LINENO 'mkdir failed'
-	exit 1
-}
-trap 'cd / && rm -rf "$tmp"' EXIT
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
 
 [[ ${.sh.version} == "$KSH_VERSION" ]] || err_exit '.sh.version != KSH_VERSION'
 unset ss
diff --git a/src/cmd/ksh93/tests/vartree1.sh b/src/cmd/ksh93/tests/vartree1.sh
index d558dc6ef..61d130973 100755
--- a/src/cmd/ksh93/tests/vartree1.sh
+++ b/src/cmd/ksh93/tests/vartree1.sh
@@ -30,9 +30,13 @@ function err_exit
 	print -u2 -r ${Command}[$1]: "${@:2}"
 	(( Errors+=1 ))
 }
-
 alias err_exit='err_exit $LINENO'
 
+Command=${0##*/}
+integer Errors=0
+
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 function build_tree
 {
 #set -o errexit -o xtrace
diff --git a/src/cmd/ksh93/tests/vartree2.sh b/src/cmd/ksh93/tests/vartree2.sh
index e3e4cffc2..b4c37cc58 100755
--- a/src/cmd/ksh93/tests/vartree2.sh
+++ b/src/cmd/ksh93/tests/vartree2.sh
@@ -30,9 +30,13 @@ function err_exit
 	print -u2 -r ${Command}[$1]: "${@:2}"
 	(( Errors+=1 ))
 }
-
 alias err_exit='err_exit $LINENO'
 
+Command=${0##*/}
+integer Errors=0
+
+[[ -d $tmp && -w $tmp ]] || { err\_exit "$LINENO" '$tmp not set; run this from shtests. Aborting.'; exit 1; }
+
 # "built_tree1" and "built_tree2" are identical except the way how they test
 # whether a variable exists:
 # - "built_tree1" uses "${varname}" != "", e.g. looking whether the variable