diff --git a/Makefile b/Makefile
index ff1cd7a643..6eda0955a2 100644
--- a/Makefile
+++ b/Makefile
@@ -168,7 +168,7 @@ get_run_prefix = $(strip $(foreach mode,$(call actual_impl,$(1))_MODE, \
 
 # Takes impl and step
 # Returns the runtest command prefix (with runtest options) for testing the given step
-get_runtest_cmd = $(call get_run_prefix,$(1),$(2),$(if $(filter cs fsharp mal tcl vb,$(1)),RAW=1,)) \
+get_runtest_cmd = $(call get_run_prefix,$(1),$(2),$(if $(filter cs fsharp mal perl tcl vb,$(1)),RAW=1)) \
 		    ../../runtest.py $(opt_HARD) $(opt_DEFERRABLE) $(opt_OPTIONAL) $(call $(1)_TEST_OPTS) $(TEST_OPTS)
 
 # Takes impl and step
diff --git a/examples/clojurewest2014.mal b/examples/clojurewest2014.mal
old mode 100755
new mode 100644
diff --git a/examples/presentation.mal b/examples/presentation.mal
old mode 100755
new mode 100644
diff --git a/impls/ada.2/run b/impls/ada.2/run
index 6efdc3de32..5ffd062744 100755
--- a/impls/ada.2/run
+++ b/impls/ada.2/run
@@ -1,2 +1,3 @@
 #!/bin/sh
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
diff --git a/impls/ada/Dockerfile b/impls/ada/Dockerfile
old mode 100755
new mode 100644
diff --git a/impls/ada/run b/impls/ada/run
index c66c2b81dc..5ffd062744 100755
--- a/impls/ada/run
+++ b/impls/ada/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
+#!/bin/sh
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
diff --git a/impls/awk/run b/impls/awk/run
index 9c3061869f..f0a9f48c35 100755
--- a/impls/awk/run
+++ b/impls/awk/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec awk -O -f $(dirname $0)/${STEP:-stepA_mal}.awk "${@}"
+#!/bin/sh
+set -Cefu
+exec awk -f ${STEP:-stepA_mal}.awk "$@"
diff --git a/impls/bash/run b/impls/bash/run
index 05081b9ce6..5ada142c2f 100755
--- a/impls/bash/run
+++ b/impls/bash/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec bash $(dirname $0)/${STEP:-stepA_mal}.sh "${@}"
+#!/bin/sh
+set -Cefu
+exec bash ${STEP:-stepA_mal}.sh "$@"
diff --git a/impls/bash/step0_repl.sh b/impls/bash/step0_repl.sh
old mode 100755
new mode 100644
index 97bce61d17..2d779dd6c8
--- a/impls/bash/step0_repl.sh
+++ b/impls/bash/step0_repl.sh
@@ -1,5 +1,3 @@
-#!/usr/bin/env bash
-
 READ () {
     read -u 0 -e -p "user> " r
 }
diff --git a/impls/bash/step1_read_print.sh b/impls/bash/step1_read_print.sh
old mode 100755
new mode 100644
index 8011fa6b86..b0eba83196
--- a/impls/bash/step1_read_print.sh
+++ b/impls/bash/step1_read_print.sh
@@ -1,5 +1,3 @@
-#!/usr/bin/env bash
-
 source $(dirname $0)/reader.sh
 source $(dirname $0)/printer.sh
 
diff --git a/impls/bash/step2_eval.sh b/impls/bash/step2_eval.sh
old mode 100755
new mode 100644
index 54d75885c3..ad0c15a255
--- a/impls/bash/step2_eval.sh
+++ b/impls/bash/step2_eval.sh
@@ -1,5 +1,3 @@
-#!/usr/bin/env bash
-
 source $(dirname $0)/reader.sh
 source $(dirname $0)/printer.sh
 
diff --git a/impls/bash/step3_env.sh b/impls/bash/step3_env.sh
old mode 100755
new mode 100644
index ba46e54306..f4433c48cb
--- a/impls/bash/step3_env.sh
+++ b/impls/bash/step3_env.sh
@@ -1,5 +1,3 @@
-#!/usr/bin/env bash
-
 source $(dirname $0)/reader.sh
 source $(dirname $0)/printer.sh
 source $(dirname $0)/env.sh
diff --git a/impls/bash/step4_if_fn_do.sh b/impls/bash/step4_if_fn_do.sh
old mode 100755
new mode 100644
index 24b45965fd..129e8959d4
--- a/impls/bash/step4_if_fn_do.sh
+++ b/impls/bash/step4_if_fn_do.sh
@@ -1,5 +1,3 @@
-#!/usr/bin/env bash
-
 source $(dirname $0)/reader.sh
 source $(dirname $0)/printer.sh
 source $(dirname $0)/env.sh
diff --git a/impls/bash/step5_tco.sh b/impls/bash/step5_tco.sh
old mode 100755
new mode 100644
index 5e30751000..c81b1ea2bf
--- a/impls/bash/step5_tco.sh
+++ b/impls/bash/step5_tco.sh
@@ -1,5 +1,3 @@
-#!/usr/bin/env bash
-
 source $(dirname $0)/reader.sh
 source $(dirname $0)/printer.sh
 source $(dirname $0)/env.sh
diff --git a/impls/bash/step6_file.sh b/impls/bash/step6_file.sh
old mode 100755
new mode 100644
index b87cbc1986..e4d0d9c202
--- a/impls/bash/step6_file.sh
+++ b/impls/bash/step6_file.sh
@@ -1,5 +1,3 @@
-#!/usr/bin/env bash
-
 source $(dirname $0)/reader.sh
 source $(dirname $0)/printer.sh
 source $(dirname $0)/env.sh
diff --git a/impls/bash/step7_quote.sh b/impls/bash/step7_quote.sh
old mode 100755
new mode 100644
index dc046f9fc2..0f0183e3b3
--- a/impls/bash/step7_quote.sh
+++ b/impls/bash/step7_quote.sh
@@ -1,5 +1,3 @@
-#!/usr/bin/env bash
-
 source $(dirname $0)/reader.sh
 source $(dirname $0)/printer.sh
 source $(dirname $0)/env.sh
diff --git a/impls/bash/step8_macros.sh b/impls/bash/step8_macros.sh
old mode 100755
new mode 100644
index 64710610e2..d832170e05
--- a/impls/bash/step8_macros.sh
+++ b/impls/bash/step8_macros.sh
@@ -1,5 +1,3 @@
-#!/usr/bin/env bash
-
 source $(dirname $0)/reader.sh
 source $(dirname $0)/printer.sh
 source $(dirname $0)/env.sh
diff --git a/impls/bash/step9_try.sh b/impls/bash/step9_try.sh
old mode 100755
new mode 100644
index bc6336ac34..7749c1b639
--- a/impls/bash/step9_try.sh
+++ b/impls/bash/step9_try.sh
@@ -1,5 +1,3 @@
-#!/usr/bin/env bash
-
 source $(dirname $0)/reader.sh
 source $(dirname $0)/printer.sh
 source $(dirname $0)/env.sh
diff --git a/impls/bash/stepA_mal.sh b/impls/bash/stepA_mal.sh
old mode 100755
new mode 100644
index f65b4b1db2..ba81dffd3c
--- a/impls/bash/stepA_mal.sh
+++ b/impls/bash/stepA_mal.sh
@@ -1,5 +1,3 @@
-#!/usr/bin/env bash
-
 source $(dirname $0)/reader.sh
 source $(dirname $0)/printer.sh
 source $(dirname $0)/env.sh
diff --git a/impls/basic/run b/impls/basic/run
index 9b394f8c0b..ccca87d142 100755
--- a/impls/basic/run
+++ b/impls/basic/run
@@ -1,8 +1,12 @@
-#!/usr/bin/env bash
-cd $(dirname $0)
-(echo "(def! -*ARGS*- (list $(for a in "${@}"; do echo -n " \"${a}\""; done)))") > .args.mal
+#!/bin/sh
+set -efu
+{
+    printf '(def! -*ARGS*- (list'
+    [ $# = 0 ] || printf ' "%s"' "$@"
+    echo '))'
+} > .args.mal
 case ${basic_MODE:-cbm} in
-    cbm)    exec cbmbasic ${STEP:-stepA_mal}.bas "${@}" ;;
-    qbasic) exec ./${STEP:-stepA_mal} "${@}" ;;
-    *)      echo "Invalid basic_MODE: ${basic_MODE}"; exit 2 ;;
+    cbm)    exec cbmbasic ${STEP:-stepA_mal}.bas "$@" ;;
+    qbasic) exec ./${STEP:-stepA_mal} "$@" ;;
+    *)      echo "Invalid basic_MODE: $basic_MODE"; exit 2 ;;
 esac
diff --git a/impls/basic/step0_repl.in.bas b/impls/basic/step0_repl.in.bas
old mode 100755
new mode 100644
diff --git a/impls/basic/step1_read_print.in.bas b/impls/basic/step1_read_print.in.bas
old mode 100755
new mode 100644
diff --git a/impls/basic/step2_eval.in.bas b/impls/basic/step2_eval.in.bas
old mode 100755
new mode 100644
diff --git a/impls/basic/step3_env.in.bas b/impls/basic/step3_env.in.bas
old mode 100755
new mode 100644
diff --git a/impls/basic/step4_if_fn_do.in.bas b/impls/basic/step4_if_fn_do.in.bas
old mode 100755
new mode 100644
diff --git a/impls/basic/step5_tco.in.bas b/impls/basic/step5_tco.in.bas
old mode 100755
new mode 100644
diff --git a/impls/basic/step6_file.in.bas b/impls/basic/step6_file.in.bas
old mode 100755
new mode 100644
diff --git a/impls/basic/step7_quote.in.bas b/impls/basic/step7_quote.in.bas
old mode 100755
new mode 100644
diff --git a/impls/basic/step8_macros.in.bas b/impls/basic/step8_macros.in.bas
old mode 100755
new mode 100644
diff --git a/impls/basic/step9_try.in.bas b/impls/basic/step9_try.in.bas
old mode 100755
new mode 100644
diff --git a/impls/basic/stepA_mal.in.bas b/impls/basic/stepA_mal.in.bas
old mode 100755
new mode 100644
diff --git a/impls/bbc-basic/run b/impls/bbc-basic/run
index b3e2049a09..8701b18cf7 100755
--- a/impls/bbc-basic/run
+++ b/impls/bbc-basic/run
@@ -1,3 +1,4 @@
-#!/usr/bin/env bash
+#!/bin/sh
+set -Cefu
 exec "${BRANDY:-sbrandy}" -size 1024k \
-    -path ../bbc-basic -quit $(dirname $0)/${STEP:-stepA_mal}.bas "${@}"
+    -quit ${STEP:-stepA_mal}.bas "$@"
diff --git a/impls/c.2/run b/impls/c.2/run
index 6efdc3de32..5ffd062744 100755
--- a/impls/c.2/run
+++ b/impls/c.2/run
@@ -1,2 +1,3 @@
 #!/bin/sh
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
diff --git a/impls/c/run b/impls/c/run
index c66c2b81dc..5ffd062744 100755
--- a/impls/c/run
+++ b/impls/c/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
+#!/bin/sh
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
diff --git a/impls/chuck/run b/impls/chuck/run
index 99137daea7..9375e4d69b 100755
--- a/impls/chuck/run
+++ b/impls/chuck/run
@@ -1,11 +1,21 @@
-#!/usr/bin/env bash
+#!/bin/sh
+set -Ceu
+step=${STEP:-stepA_mal}.ck
+
 regex_chugin=${REGEX_CHUGIN:-/usr/local/lib/chuck/1.5.2.5/RegEx.chug}
-if [[ ! -f "$regex_chugin" ]]; then
-    echo "Set \$REGEX_CHUGIN to the absolute path of RegEx.chug"; exit 1
+if [ ! -f "$regex_chugin" ]; then
+    echo 'Set $REGEX_CHUGIN to the absolute path of RegEx.chug'
+    exit 1
 fi
 
-imports=$(grep "^ *// *@import" "$(dirname $0)/${STEP:-stepA_mal}.ck" | awk '{print $3}')
-imports=$(for i in ${imports}; do ls $(dirname $0)/${i}; done)
-old_IFS="${IFS}"; IFS=$'\a'; export CHUCK_ARGS="${*}"; IFS="${old_IFS}"
+# The globs will be expanded in the exec line.
+imports=$(sed -n "s|^ *// *@import *||p" $step)
+
+separator=$(printf '\a')
+for x; do
+    CHUCK_ARGS="${CHUCK_ARGS:+$CHUCK_ARGS$separator}$x"
+done
+export CHUCK_ARGS
 
-exec chuck --caution-to-the-wind --silent --chugin:"$regex_chugin" ${imports} $(dirname $-1)/${STEP:-stepA_mal}.ck
+exec chuck --caution-to-the-wind --silent --chugin:"$regex_chugin" \
+     $imports $step
diff --git a/impls/clojure/run b/impls/clojure/run
index 5fe4d92804..0c188c559a 100755
--- a/impls/clojure/run
+++ b/impls/clojure/run
@@ -1,8 +1,10 @@
-#!/usr/bin/env bash
-export PATH=$PATH:$(dirname $0)/node_modules/.bin
+#!/bin/sh
+set -Cefu
+export PATH="$PATH:node_modules/.bin"
 STEP=${STEP:-stepA_mal}
-if [ "${clojure_MODE}" = "cljs" ]; then
-  exec lumo -c $(dirname $0)/src -m mal.${STEP//_/-} "${@}"
-else
-  exec java -jar $(dirname $0)/target/${STEP}.jar "${@}"
-fi
+case ${clojure_MODE:-clj} in
+    cljs) exec lumo -c src -m mal.$(echo $STEP | tr _ -) "$@" ;;
+    clj)  exec java -jar target/$STEP.jar "$@" ;;
+esac
+echo "Invalid clojure_MODE: $clojure_MODE"
+exit 1
diff --git a/impls/coffee/run b/impls/coffee/run
index 84deffb471..58f481b9ec 100755
--- a/impls/coffee/run
+++ b/impls/coffee/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec coffee $(dirname $0)/${STEP:-stepA_mal}.coffee "${@}"
+#!/bin/sh
+set -Cefu
+exec coffee ${STEP:-stepA_mal}.coffee "$@"
diff --git a/impls/common-lisp/run b/impls/common-lisp/run
index c66c2b81dc..5ffd062744 100755
--- a/impls/common-lisp/run
+++ b/impls/common-lisp/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
+#!/bin/sh
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
diff --git a/impls/cpp/run b/impls/cpp/run
index c66c2b81dc..5ffd062744 100755
--- a/impls/cpp/run
+++ b/impls/cpp/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
+#!/bin/sh
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
diff --git a/impls/crystal/run b/impls/crystal/run
index a42a7e149d..bf24a176db 100755
--- a/impls/crystal/run
+++ b/impls/crystal/run
@@ -1,2 +1,3 @@
 #!/bin/sh
-exec $(dirname $0)/bin/${STEP:-stepA_mal} "${@}"
+set -Cefu
+exec bin/${STEP:-stepA_mal} "$@"
diff --git a/impls/crystal/step0_repl.cr b/impls/crystal/step0_repl.cr
old mode 100755
new mode 100644
index a9c67d68f2..b6a1bfba32
--- a/impls/crystal/step0_repl.cr
+++ b/impls/crystal/step0_repl.cr
@@ -1,5 +1,3 @@
-#! /usr/bin/env crystal run
-
 require "readline"
 
 # Note:
diff --git a/impls/crystal/step1_read_print.cr b/impls/crystal/step1_read_print.cr
old mode 100755
new mode 100644
index 4d7195895e..8c5ddffb9e
--- a/impls/crystal/step1_read_print.cr
+++ b/impls/crystal/step1_read_print.cr
@@ -1,5 +1,3 @@
-#! /usr/bin/env crystal run
-
 require "readline"
 require "./reader"
 require "./printer"
diff --git a/impls/crystal/step2_eval.cr b/impls/crystal/step2_eval.cr
old mode 100755
new mode 100644
index f8713571cd..dd8f2533d1
--- a/impls/crystal/step2_eval.cr
+++ b/impls/crystal/step2_eval.cr
@@ -1,5 +1,3 @@
-#! /usr/bin/env crystal run
-
 require "readline"
 require "./reader"
 require "./printer"
diff --git a/impls/crystal/step3_env.cr b/impls/crystal/step3_env.cr
old mode 100755
new mode 100644
index a17d79779f..fd77be8e46
--- a/impls/crystal/step3_env.cr
+++ b/impls/crystal/step3_env.cr
@@ -1,5 +1,3 @@
-#! /usr/bin/env crystal run
-
 require "readline"
 require "./reader"
 require "./printer"
diff --git a/impls/crystal/step4_if_fn_do.cr b/impls/crystal/step4_if_fn_do.cr
old mode 100755
new mode 100644
index fb33c8911d..251629332d
--- a/impls/crystal/step4_if_fn_do.cr
+++ b/impls/crystal/step4_if_fn_do.cr
@@ -1,5 +1,3 @@
-#! /usr/bin/env crystal run
-
 require "readline"
 require "./reader"
 require "./printer"
diff --git a/impls/crystal/step5_tco.cr b/impls/crystal/step5_tco.cr
old mode 100755
new mode 100644
index 508ed0b176..72a9489606
--- a/impls/crystal/step5_tco.cr
+++ b/impls/crystal/step5_tco.cr
@@ -1,5 +1,3 @@
-#! /usr/bin/env crystal run
-
 require "readline"
 require "./reader"
 require "./printer"
diff --git a/impls/crystal/step6_file.cr b/impls/crystal/step6_file.cr
old mode 100755
new mode 100644
index a7a95e170c..2eff3ba8d0
--- a/impls/crystal/step6_file.cr
+++ b/impls/crystal/step6_file.cr
@@ -1,5 +1,3 @@
-#! /usr/bin/env crystal run
-
 require "readline"
 require "./reader"
 require "./printer"
diff --git a/impls/crystal/step7_quote.cr b/impls/crystal/step7_quote.cr
old mode 100755
new mode 100644
index b935061fa2..0455d143db
--- a/impls/crystal/step7_quote.cr
+++ b/impls/crystal/step7_quote.cr
@@ -1,5 +1,3 @@
-#! /usr/bin/env crystal run
-
 require "readline"
 require "./reader"
 require "./printer"
diff --git a/impls/crystal/step8_macros.cr b/impls/crystal/step8_macros.cr
old mode 100755
new mode 100644
index 2c7ac4e755..57b6063d82
--- a/impls/crystal/step8_macros.cr
+++ b/impls/crystal/step8_macros.cr
@@ -1,5 +1,3 @@
-#! /usr/bin/env crystal run
-
 require "readline"
 require "./reader"
 require "./printer"
diff --git a/impls/crystal/step9_try.cr b/impls/crystal/step9_try.cr
old mode 100755
new mode 100644
index 984158b28f..bfc8a70572
--- a/impls/crystal/step9_try.cr
+++ b/impls/crystal/step9_try.cr
@@ -1,5 +1,3 @@
-#! /usr/bin/env crystal run
-
 require "readline"
 require "./reader"
 require "./printer"
diff --git a/impls/crystal/stepA_mal.cr b/impls/crystal/stepA_mal.cr
old mode 100755
new mode 100644
index 2857c89d13..65fb8e9f8b
--- a/impls/crystal/stepA_mal.cr
+++ b/impls/crystal/stepA_mal.cr
@@ -1,5 +1,3 @@
-#! /usr/bin/env crystal run
-
 require "colorize"
 
 require "readline"
diff --git a/impls/cs/Makefile b/impls/cs/Makefile
index 52529a915b..7c6165b5e0 100644
--- a/impls/cs/Makefile
+++ b/impls/cs/Makefile
@@ -24,13 +24,13 @@ all: $(patsubst %.cs,%.exe,$(SRCS))
 
 dist: mal.exe mal
 
-mal.exe: $(patsubst %.cs,%.exe,$(word $(words $(SOURCES)),$(SOURCES)))
+mal.exe: $(patsubst %.cs,%.exe,$(lastword $(SOURCES)))
 	cp $< $@
 
 # NOTE/WARNING: static linking triggers mono libraries LGPL
 # distribution requirements.
 # http://www.mono-project.com/archived/guiderunning_mono_applications/
-mal: $(patsubst %.cs,%.exe,$(word $(words $(SOURCES)),$(SOURCES))) mal.dll
+mal: $(patsubst %.cs,%.exe,$(lastword $(SOURCES))) mal.dll
 	mkbundle --static -o $@ $+ --deps
 
 mal.dll: $(LIB_SRCS)
diff --git a/impls/cs/run b/impls/cs/run
index 5c5642646f..8ea6fdbea1 100755
--- a/impls/cs/run
+++ b/impls/cs/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec mono $(dirname $0)/${STEP:-stepA_mal}.exe ${RAW:+--raw} "${@}"
+#!/bin/sh
+set -Cefu
+exec mono ${STEP:-stepA_mal}.exe ${RAW:+--raw} "$@"
diff --git a/impls/d/run b/impls/d/run
index c66c2b81dc..5ffd062744 100755
--- a/impls/d/run
+++ b/impls/d/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
+#!/bin/sh
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
diff --git a/impls/dart/run b/impls/dart/run
index 6f3ab8bca3..d8320472de 100755
--- a/impls/dart/run
+++ b/impls/dart/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec dart --checked $(dirname $0)/${STEP:-stepA_mal}.dart "${@}"
+#!/bin/sh
+set -Cefu
+exec dart --checked ${STEP:-stepA_mal}.dart "$@"
diff --git a/impls/elisp/run b/impls/elisp/run
index cb0387403c..16aaeb34c5 100755
--- a/impls/elisp/run
+++ b/impls/elisp/run
@@ -1,3 +1,5 @@
 #!/bin/sh
-dir=$(dirname $0)
-exec emacs -Q --batch -L $dir --eval "(setq text-quoting-style 'straight)" --load $dir/${STEP:-stepA_mal}.elc "${@}"
+set -Cefu
+exec emacs -Q --batch -L . \
+     --eval "(setq text-quoting-style 'straight)" \
+     --load ${STEP:-stepA_mal}.elc "$@"
diff --git a/impls/elixir/run b/impls/elixir/run
index bfd505014b..8c4f3f8eeb 100755
--- a/impls/elixir/run
+++ b/impls/elixir/run
@@ -1,3 +1,3 @@
-#!/usr/bin/env bash
-cd $(dirname $0)
-exec mix ${STEP:-stepA_mal} "${@}"
+#!/bin/sh
+set -Cefu
+exec mix ${STEP:-stepA_mal} "$@"
diff --git a/impls/elm/run b/impls/elm/run
index d22e4fbeac..7235b16b18 100755
--- a/impls/elm/run
+++ b/impls/elm/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec node $(dirname $0)/bootstrap.js ${STEP:-stepA_mal} "${@}"
+#!/bin/sh
+set -Cefu
+exec node bootstrap.js ${STEP:-stepA_mal} "$@"
diff --git a/impls/erlang/run b/impls/erlang/run
index c66c2b81dc..5ffd062744 100755
--- a/impls/erlang/run
+++ b/impls/erlang/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
+#!/bin/sh
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
diff --git a/impls/es6/run b/impls/es6/run
index 54e8932d5c..1c8b71b919 100755
--- a/impls/es6/run
+++ b/impls/es6/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec node $(dirname $0)/${STEP:-stepA_mal}.mjs "${@}"
+#!/bin/sh
+set -Cefu
+exec node ${STEP:-stepA_mal}.mjs "$@"
diff --git a/impls/factor/run b/impls/factor/run
index bb6d41f1da..b2e0210719 100755
--- a/impls/factor/run
+++ b/impls/factor/run
@@ -1,2 +1,4 @@
-#!/usr/bin/env bash
-exec factor $(dirname $0)/${STEP:-stepA_mal}/${STEP:-stepA_mal}.factor "${@}"
+#!/bin/sh
+set -Cefu
+step=${STEP:-stepA_mal}
+exec factor $step/$step.factor "$@"
diff --git a/impls/factor/step0_repl/step0_repl.factor b/impls/factor/step0_repl/step0_repl.factor
old mode 100755
new mode 100644
diff --git a/impls/factor/step1_read_print/step1_read_print.factor b/impls/factor/step1_read_print/step1_read_print.factor
old mode 100755
new mode 100644
diff --git a/impls/factor/step2_eval/step2_eval.factor b/impls/factor/step2_eval/step2_eval.factor
old mode 100755
new mode 100644
diff --git a/impls/factor/step3_env/step3_env.factor b/impls/factor/step3_env/step3_env.factor
old mode 100755
new mode 100644
diff --git a/impls/factor/step4_if_fn_do/step4_if_fn_do.factor b/impls/factor/step4_if_fn_do/step4_if_fn_do.factor
old mode 100755
new mode 100644
diff --git a/impls/factor/step5_tco/step5_tco.factor b/impls/factor/step5_tco/step5_tco.factor
old mode 100755
new mode 100644
diff --git a/impls/factor/step6_file/step6_file.factor b/impls/factor/step6_file/step6_file.factor
old mode 100755
new mode 100644
diff --git a/impls/factor/step7_quote/step7_quote.factor b/impls/factor/step7_quote/step7_quote.factor
old mode 100755
new mode 100644
diff --git a/impls/factor/step8_macros/step8_macros.factor b/impls/factor/step8_macros/step8_macros.factor
old mode 100755
new mode 100644
diff --git a/impls/factor/step9_try/step9_try.factor b/impls/factor/step9_try/step9_try.factor
old mode 100755
new mode 100644
diff --git a/impls/factor/stepA_mal/stepA_mal.factor b/impls/factor/stepA_mal/stepA_mal.factor
old mode 100755
new mode 100644
diff --git a/impls/fantom/run b/impls/fantom/run
index b0b70cf57b..72c94f7416 100755
--- a/impls/fantom/run
+++ b/impls/fantom/run
@@ -1,4 +1,5 @@
-#!/usr/bin/env bash
+#!/bin/sh
+set -Cefu
 export FAN_ENV=util::PathEnv
-export FAN_ENV_PATH="$(dirname $0)"
+export FAN_ENV_PATH=.
 exec fan ${STEP:-stepA_mal} "$@"
diff --git a/impls/fennel/run b/impls/fennel/run
index 5842447c37..12cbae82c3 100755
--- a/impls/fennel/run
+++ b/impls/fennel/run
@@ -1,3 +1,3 @@
-#!/usr/bin/env bash
-
-exec fennel $(dirname $0)/${STEP:-stepA_mal}.fnl "${@}"
+#!/bin/sh
+set -Cefu
+exec fennel ${STEP:-stepA_mal}.fnl "$@"
diff --git a/impls/forth/run b/impls/forth/run
index 0a45c57df5..3290045678 100755
--- a/impls/forth/run
+++ b/impls/forth/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec gforth $(dirname $0)/${STEP:-stepA_mal}.fs "${@}"
+#!/bin/sh
+set -Cefu
+exec gforth ${STEP:-stepA_mal}.fs "$@"
diff --git a/impls/fsharp/run b/impls/fsharp/run
index 5c5642646f..8ea6fdbea1 100755
--- a/impls/fsharp/run
+++ b/impls/fsharp/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec mono $(dirname $0)/${STEP:-stepA_mal}.exe ${RAW:+--raw} "${@}"
+#!/bin/sh
+set -Cefu
+exec mono ${STEP:-stepA_mal}.exe ${RAW:+--raw} "$@"
diff --git a/impls/gnu-smalltalk/run b/impls/gnu-smalltalk/run
index 740459af26..746651207f 100755
--- a/impls/gnu-smalltalk/run
+++ b/impls/gnu-smalltalk/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec gst -f $(dirname $0)/${STEP:-stepA_mal}.st "${@}"
+#!/bin/sh
+set -Cefu
+exec gst -f ${STEP:-stepA_mal}.st "$@"
diff --git a/impls/go/run b/impls/go/run
index c66c2b81dc..5ffd062744 100755
--- a/impls/go/run
+++ b/impls/go/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
+#!/bin/sh
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
diff --git a/impls/groovy/run b/impls/groovy/run
index b64ea39452..9733f7c8a5 100755
--- a/impls/groovy/run
+++ b/impls/groovy/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec groovy $(dirname $0)/${STEP:-stepA_mal}.groovy "${@}"
+#!/bin/sh
+set -Cefu
+exec groovy ${STEP:-stepA_mal}.groovy "$@"
diff --git a/impls/guile/run b/impls/guile/run
index 6d9e58d123..747d2c6932 100755
--- a/impls/guile/run
+++ b/impls/guile/run
@@ -1,3 +1,4 @@
-#!/usr/bin/env bash
+#!/bin/sh
+set -Cefu
 # XDG_CACHE_HOME is where guile stores the compiled files
-XDG_CACHE_HOME=.cache/ exec guile -L $(dirname $0) $(dirname $0)/${STEP:-stepA_mal}.scm "${@}"
+XDG_CACHE_HOME=.cache/ exec guile -L . ${STEP:-stepA_mal}.scm "$@"
diff --git a/impls/hare/run b/impls/hare/run
index 373d352735..5ffd062744 100755
--- a/impls/hare/run
+++ b/impls/hare/run
@@ -1,3 +1,3 @@
-#!/usr/bin/env bash
-
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
\ No newline at end of file
+#!/bin/sh
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
diff --git a/impls/haskell/run b/impls/haskell/run
index 6efdc3de32..5ffd062744 100755
--- a/impls/haskell/run
+++ b/impls/haskell/run
@@ -1,2 +1,3 @@
 #!/bin/sh
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
diff --git a/impls/haxe/run b/impls/haxe/run
index 3bb679ae65..fdd0476b6a 100755
--- a/impls/haxe/run
+++ b/impls/haxe/run
@@ -1,8 +1,9 @@
-#!/usr/bin/env bash
+#!/bin/sh
+set -Cefu
 case ${haxe_MODE:-neko} in
-    neko)   exec neko    $(dirname $0)/${STEP:-stepA_mal}.n   "${@}" ;;
-    python) exec python3 $(dirname $0)/${STEP:-stepA_mal}.py  "${@}" ;;
-    js)     exec node    $(dirname $0)/${STEP:-stepA_mal}.js  "${@}" ;;
-    cpp)    exec         $(dirname $0)/cpp/${STEP:-stepA_mal} "${@}" ;;
-    *) echo "Invalid haxe_MODE: ${haxe_MODE}"; exit 2 ;;
+    neko)   exec neko    ${STEP:-stepA_mal}.n   "$@" ;;
+    python) exec python3 ${STEP:-stepA_mal}.py  "$@" ;;
+    js)     exec node    ${STEP:-stepA_mal}.js  "$@" ;;
+    cpp)    exec         cpp/${STEP:-stepA_mal} "$@" ;;
+    *) echo "Invalid haxe_MODE: $haxe_MODE"; exit 2 ;;
 esac
diff --git a/impls/hy/run b/impls/hy/run
index e203849508..777d500345 100755
--- a/impls/hy/run
+++ b/impls/hy/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec $(dirname $0)/${STEP:-stepA_mal}.hy "${@}"
+#!/bin/sh
+set -Cefu
+exec hy ${STEP:-stepA_mal}.hy "$@"
diff --git a/impls/hy/step0_repl.hy b/impls/hy/step0_repl.hy
old mode 100755
new mode 100644
index d651bbf0ef..5b837b721b
--- a/impls/hy/step0_repl.hy
+++ b/impls/hy/step0_repl.hy
@@ -1,5 +1,3 @@
-#!/usr/bin/env hy
-
 (defn READ [str]
   str)
 
diff --git a/impls/hy/step1_read_print.hy b/impls/hy/step1_read_print.hy
old mode 100755
new mode 100644
index ba8670e14b..61af6fda01
--- a/impls/hy/step1_read_print.hy
+++ b/impls/hy/step1_read_print.hy
@@ -1,5 +1,3 @@
-#!/usr/bin/env hy
-
 (import sys traceback)
 (import [reader [read-str Blank]])
 (import [printer [pr-str]])
diff --git a/impls/hy/step2_eval.hy b/impls/hy/step2_eval.hy
old mode 100755
new mode 100644
index adfc2a16a6..1ade3ab4dd
--- a/impls/hy/step2_eval.hy
+++ b/impls/hy/step2_eval.hy
@@ -1,5 +1,3 @@
-#!/usr/bin/env hy
-
 (import sys traceback)
 (import [reader [read-str Blank]])
 (import [printer [pr-str]])
diff --git a/impls/hy/step3_env.hy b/impls/hy/step3_env.hy
old mode 100755
new mode 100644
index 26fca8fa7a..1a92f421f7
--- a/impls/hy/step3_env.hy
+++ b/impls/hy/step3_env.hy
@@ -1,5 +1,3 @@
-#!/usr/bin/env hy
-
 (import [hy.models [HySymbol :as Sym]])
 (import sys traceback)
 (import [reader [read-str Blank]])
diff --git a/impls/hy/step4_if_fn_do.hy b/impls/hy/step4_if_fn_do.hy
old mode 100755
new mode 100644
index ae01bf32a5..c65b49c991
--- a/impls/hy/step4_if_fn_do.hy
+++ b/impls/hy/step4_if_fn_do.hy
@@ -1,5 +1,3 @@
-#!/usr/bin/env hy
-
 (import [hy.models [HySymbol :as Sym]])
 (import sys traceback)
 (import [mal_types [MalException]])
diff --git a/impls/hy/step5_tco.hy b/impls/hy/step5_tco.hy
old mode 100755
new mode 100644
index 6b364657ab..6beef1a319
--- a/impls/hy/step5_tco.hy
+++ b/impls/hy/step5_tco.hy
@@ -1,5 +1,3 @@
-#!/usr/bin/env hy
-
 (import [hy.models [HySymbol :as Sym]])
 (import sys traceback)
 (import [mal_types [MalException]])
diff --git a/impls/hy/step6_file.hy b/impls/hy/step6_file.hy
old mode 100755
new mode 100644
index 9cf4c7380a..45f871aff1
--- a/impls/hy/step6_file.hy
+++ b/impls/hy/step6_file.hy
@@ -1,5 +1,3 @@
-#!/usr/bin/env hy
-
 (import [hy.models [HyString :as Str HySymbol :as Sym]])
 (import sys traceback)
 (import [mal_types [MalException]])
diff --git a/impls/hy/step7_quote.hy b/impls/hy/step7_quote.hy
old mode 100755
new mode 100644
index 757852db5f..de7252f2de
--- a/impls/hy/step7_quote.hy
+++ b/impls/hy/step7_quote.hy
@@ -1,5 +1,3 @@
-#!/usr/bin/env hy
-
 (import [hy.models [HyString :as Str HySymbol :as Sym]])
 (import sys traceback)
 (import [mal_types [MalException]])
diff --git a/impls/hy/step8_macros.hy b/impls/hy/step8_macros.hy
old mode 100755
new mode 100644
index 97ee0ee46c..806914b5a6
--- a/impls/hy/step8_macros.hy
+++ b/impls/hy/step8_macros.hy
@@ -1,5 +1,3 @@
-#!/usr/bin/env hy
-
 (import [hy.models [HyString :as Str HySymbol :as Sym]])
 (import sys traceback)
 (import [mal_types [MalException]])
diff --git a/impls/hy/step9_try.hy b/impls/hy/step9_try.hy
old mode 100755
new mode 100644
index 5dc44a0cf0..f852b53fa7
--- a/impls/hy/step9_try.hy
+++ b/impls/hy/step9_try.hy
@@ -1,5 +1,3 @@
-#!/usr/bin/env hy
-
 (import [hy.models [HyString :as Str HySymbol :as Sym]])
 (import sys traceback)
 (import [mal_types [MalException]])
diff --git a/impls/hy/stepA_mal.hy b/impls/hy/stepA_mal.hy
old mode 100755
new mode 100644
index 3e881fdab6..dbffa8835e
--- a/impls/hy/stepA_mal.hy
+++ b/impls/hy/stepA_mal.hy
@@ -1,5 +1,3 @@
-#!/usr/bin/env hy
-
 (import [hy.models [HyString :as Str HySymbol :as Sym]])
 (import sys traceback)
 (import [mal_types [MalException]])
diff --git a/impls/io/run b/impls/io/run
index d49d10a227..6d84acab3b 100755
--- a/impls/io/run
+++ b/impls/io/run
@@ -1,3 +1,3 @@
-#!/usr/bin/env bash
-
-io $(dirname $0)/${STEP:-stepA_mal}.io "$@"
+#!/bin/sh
+set -Cefu
+exec io ${STEP:-stepA_mal}.io "$@"
diff --git a/impls/janet/run b/impls/janet/run
index f4782c8fae..59c0c1b628 100755
--- a/impls/janet/run
+++ b/impls/janet/run
@@ -1,2 +1,3 @@
 #!/bin/sh
-exec janet $(dirname $0)/${STEP:-stepA_mal}.janet "${@}"
+set -Cefu
+exec janet ${STEP:-stepA_mal}.janet "$@"
diff --git a/impls/java-truffle/run b/impls/java-truffle/run
index c5ca27135f..5e6271cbe4 100755
--- a/impls/java-truffle/run
+++ b/impls/java-truffle/run
@@ -1,4 +1,5 @@
-#!/usr/bin/env bash
+#!/bin/sh
+set -Cefu
 
 CP=$(gradle -q --console plain printClasspath)
 
diff --git a/impls/java/run b/impls/java/run
index 670f45c4db..567e9f649c 100755
--- a/impls/java/run
+++ b/impls/java/run
@@ -1,9 +1,8 @@
-#!/usr/bin/env bash
-args=""
-if [ "$#" -gt 0 ]; then
-    args="-Dexec.args='$1'"
-    for a in "${@:2}"; do
-        args="$args '$a'"
-    done
-fi
-exec mvn -quiet -e exec:java -Dexec.mainClass="mal.${STEP:-stepA_mal}" ${args:+"$args"}
+#!/bin/sh
+set -Cefu
+for a; do
+    args="${args:+$args }'$a'"
+done
+exec mvn -quiet -e exec:java \
+     -Dexec.mainClass=mal.${STEP:-stepA_mal} \
+     ${args:+"-Dexec.args=$args"}
diff --git a/impls/js/run b/impls/js/run
index 1148122a23..d1135e76d4 100755
--- a/impls/js/run
+++ b/impls/js/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec node $(dirname $0)/${STEP:-stepA_mal}.js "${@}"
+#!/bin/sh
+set -Cefu
+exec node ${STEP:-stepA_mal}.js "$@"
diff --git a/impls/julia/run b/impls/julia/run
index dd149451f1..3a08886fca 100755
--- a/impls/julia/run
+++ b/impls/julia/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec julia $(dirname $0)/${STEP:-stepA_mal}.jl "${@}"
+#!/bin/sh
+set -Cefu
+exec julia ${STEP:-stepA_mal}.jl "$@"
diff --git a/impls/julia/step0_repl.jl b/impls/julia/step0_repl.jl
old mode 100755
new mode 100644
index 049cde1418..e26734a05e
--- a/impls/julia/step0_repl.jl
+++ b/impls/julia/step0_repl.jl
@@ -1,5 +1,3 @@
-#!/usr/bin/env julia
-
 push!(LOAD_PATH, pwd(), "/usr/share/julia/base")
 import readline_mod
 
diff --git a/impls/julia/step1_read_print.jl b/impls/julia/step1_read_print.jl
old mode 100755
new mode 100644
index 604b1f9c3d..9991ebd308
--- a/impls/julia/step1_read_print.jl
+++ b/impls/julia/step1_read_print.jl
@@ -1,5 +1,3 @@
-#!/usr/bin/env julia
-
 push!(LOAD_PATH, pwd(), "/usr/share/julia/base")
 import readline_mod
 import reader
diff --git a/impls/julia/step2_eval.jl b/impls/julia/step2_eval.jl
old mode 100755
new mode 100644
index b64ca9e17c..cc97dbf81e
--- a/impls/julia/step2_eval.jl
+++ b/impls/julia/step2_eval.jl
@@ -1,5 +1,3 @@
-#!/usr/bin/env julia
-
 push!(LOAD_PATH, pwd(), "/usr/share/julia/base")
 import readline_mod
 import reader
diff --git a/impls/julia/step3_env.jl b/impls/julia/step3_env.jl
old mode 100755
new mode 100644
index b1cdd6c595..e4d8a895de
--- a/impls/julia/step3_env.jl
+++ b/impls/julia/step3_env.jl
@@ -1,5 +1,3 @@
-#!/usr/bin/env julia
-
 push!(LOAD_PATH, pwd(), "/usr/share/julia/base")
 import readline_mod
 import reader
diff --git a/impls/julia/step4_if_fn_do.jl b/impls/julia/step4_if_fn_do.jl
old mode 100755
new mode 100644
index 70334f4337..ffb421eba0
--- a/impls/julia/step4_if_fn_do.jl
+++ b/impls/julia/step4_if_fn_do.jl
@@ -1,5 +1,3 @@
-#!/usr/bin/env julia
-
 push!(LOAD_PATH, pwd(), "/usr/share/julia/base")
 import readline_mod
 import reader
diff --git a/impls/julia/step5_tco.jl b/impls/julia/step5_tco.jl
old mode 100755
new mode 100644
index 08ed0659cf..9741829cef
--- a/impls/julia/step5_tco.jl
+++ b/impls/julia/step5_tco.jl
@@ -1,5 +1,3 @@
-#!/usr/bin/env julia
-
 push!(LOAD_PATH, pwd(), "/usr/share/julia/base")
 import readline_mod
 import reader
diff --git a/impls/julia/step6_file.jl b/impls/julia/step6_file.jl
old mode 100755
new mode 100644
index 0c39d0516e..3654228609
--- a/impls/julia/step6_file.jl
+++ b/impls/julia/step6_file.jl
@@ -1,5 +1,3 @@
-#!/usr/bin/env julia
-
 push!(LOAD_PATH, pwd(), "/usr/share/julia/base")
 import readline_mod
 import reader
diff --git a/impls/julia/step7_quote.jl b/impls/julia/step7_quote.jl
old mode 100755
new mode 100644
index 86148cfd67..66b43232d5
--- a/impls/julia/step7_quote.jl
+++ b/impls/julia/step7_quote.jl
@@ -1,5 +1,3 @@
-#!/usr/bin/env julia
-
 push!(LOAD_PATH, pwd(), "/usr/share/julia/base")
 import readline_mod
 import reader
diff --git a/impls/julia/step8_macros.jl b/impls/julia/step8_macros.jl
old mode 100755
new mode 100644
index 5dee5a32e1..ef460889bd
--- a/impls/julia/step8_macros.jl
+++ b/impls/julia/step8_macros.jl
@@ -1,5 +1,3 @@
-#!/usr/bin/env julia
-
 push!(LOAD_PATH, pwd(), "/usr/share/julia/base")
 import readline_mod
 import reader
diff --git a/impls/julia/step9_try.jl b/impls/julia/step9_try.jl
old mode 100755
new mode 100644
index 73c18d01df..ca902b98a1
--- a/impls/julia/step9_try.jl
+++ b/impls/julia/step9_try.jl
@@ -1,5 +1,3 @@
-#!/usr/bin/env julia
-
 push!(LOAD_PATH, pwd(), "/usr/share/julia/base")
 import readline_mod
 import reader
diff --git a/impls/julia/stepA_mal.jl b/impls/julia/stepA_mal.jl
old mode 100755
new mode 100644
index efeabef3e6..6f71851eed
--- a/impls/julia/stepA_mal.jl
+++ b/impls/julia/stepA_mal.jl
@@ -1,5 +1,3 @@
-#!/usr/bin/env julia
-
 push!(LOAD_PATH, pwd(), "/usr/share/julia/base")
 import readline_mod
 import reader
diff --git a/impls/kotlin/run b/impls/kotlin/run
index c5a1f3c10f..f77cf44639 100755
--- a/impls/kotlin/run
+++ b/impls/kotlin/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec java -jar $(dirname $0)/${STEP:-stepA_mal}.jar "${@}"
+#!/bin/sh
+set -Cefu
+exec java -jar ${STEP:-stepA_mal}.jar "$@"
diff --git a/impls/latex3/run b/impls/latex3/run
index 7a05291e20..c8965f8caf 100755
--- a/impls/latex3/run
+++ b/impls/latex3/run
@@ -2,7 +2,6 @@
 set -Cefu
 
 # LaTeX creates temporary files in the current directory.
-cd $(dirname $0)
 
 # There is no way to directly provide command line arguments to LaTeX,
 # use an intermediate file.
diff --git a/impls/livescript/run b/impls/livescript/run
index 1148122a23..d1135e76d4 100755
--- a/impls/livescript/run
+++ b/impls/livescript/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec node $(dirname $0)/${STEP:-stepA_mal}.js "${@}"
+#!/bin/sh
+set -Cefu
+exec node ${STEP:-stepA_mal}.js "$@"
diff --git a/impls/logo/run b/impls/logo/run
index f4a73d98c1..422aa8fc40 100755
--- a/impls/logo/run
+++ b/impls/logo/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec ucblogo $(dirname $0)/${STEP:-stepA_mal}.lg - "${@}"
+#!/bin/sh
+set -Cefu
+exec ucblogo ${STEP:-stepA_mal}.lg - "$@"
diff --git a/impls/lua/run b/impls/lua/run
index a53fbc60ba..78595ba01f 100755
--- a/impls/lua/run
+++ b/impls/lua/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec lua $(dirname $0)/${STEP:-stepA_mal}.lua "${@}"
+#!/bin/sh
+set -Cefu
+exec lua ${STEP:-stepA_mal}.lua "$@"
diff --git a/impls/lua/step0_repl.lua b/impls/lua/step0_repl.lua
old mode 100755
new mode 100644
index bb082a599d..94290842f8
--- a/impls/lua/step0_repl.lua
+++ b/impls/lua/step0_repl.lua
@@ -1,5 +1,3 @@
-#!/usr/bin/env lua
-
 local readline = require('readline')
 
 function READ(str)
diff --git a/impls/lua/step1_read_print.lua b/impls/lua/step1_read_print.lua
old mode 100755
new mode 100644
index 78cde8c1fe..db7ec5d2dd
--- a/impls/lua/step1_read_print.lua
+++ b/impls/lua/step1_read_print.lua
@@ -1,5 +1,3 @@
-#!/usr/bin/env lua
-
 local readline = require('readline')
 local types = require('types')
 local reader = require('reader')
diff --git a/impls/lua/step2_eval.lua b/impls/lua/step2_eval.lua
old mode 100755
new mode 100644
index 0bb44d2a26..3259c87ca1
--- a/impls/lua/step2_eval.lua
+++ b/impls/lua/step2_eval.lua
@@ -1,5 +1,3 @@
-#!/usr/bin/env lua
-
 local table = require('table')
 
 local readline = require('readline')
diff --git a/impls/lua/step3_env.lua b/impls/lua/step3_env.lua
old mode 100755
new mode 100644
index 297083deed..93afe5d885
--- a/impls/lua/step3_env.lua
+++ b/impls/lua/step3_env.lua
@@ -1,5 +1,3 @@
-#!/usr/bin/env lua
-
 local table = require('table')
 
 local readline = require('readline')
diff --git a/impls/lua/step4_if_fn_do.lua b/impls/lua/step4_if_fn_do.lua
old mode 100755
new mode 100644
index f69c2379ed..d89653c391
--- a/impls/lua/step4_if_fn_do.lua
+++ b/impls/lua/step4_if_fn_do.lua
@@ -1,5 +1,3 @@
-#!/usr/bin/env lua
-
 local table = require('table')
 
 local readline = require('readline')
diff --git a/impls/lua/step5_tco.lua b/impls/lua/step5_tco.lua
old mode 100755
new mode 100644
index 923a148357..d985db589a
--- a/impls/lua/step5_tco.lua
+++ b/impls/lua/step5_tco.lua
@@ -1,5 +1,3 @@
-#!/usr/bin/env lua
-
 local table = require('table')
 
 local readline = require('readline')
diff --git a/impls/lua/step6_file.lua b/impls/lua/step6_file.lua
old mode 100755
new mode 100644
index 2f5abf7d57..2d8a952734
--- a/impls/lua/step6_file.lua
+++ b/impls/lua/step6_file.lua
@@ -1,5 +1,3 @@
-#!/usr/bin/env lua
-
 local table = require('table')
 
 local readline = require('readline')
diff --git a/impls/lua/step7_quote.lua b/impls/lua/step7_quote.lua
old mode 100755
new mode 100644
index 67de77665f..0a334d58d0
--- a/impls/lua/step7_quote.lua
+++ b/impls/lua/step7_quote.lua
@@ -1,5 +1,3 @@
-#!/usr/bin/env lua
-
 local table = require('table')
 
 local readline = require('readline')
diff --git a/impls/lua/step8_macros.lua b/impls/lua/step8_macros.lua
old mode 100755
new mode 100644
index ce12dc864e..b33ffb8f88
--- a/impls/lua/step8_macros.lua
+++ b/impls/lua/step8_macros.lua
@@ -1,5 +1,3 @@
-#!/usr/bin/env lua
-
 local table = require('table')
 
 local readline = require('readline')
diff --git a/impls/lua/step9_try.lua b/impls/lua/step9_try.lua
old mode 100755
new mode 100644
index a6fe507d5f..2634ac953a
--- a/impls/lua/step9_try.lua
+++ b/impls/lua/step9_try.lua
@@ -1,5 +1,3 @@
-#!/usr/bin/env lua
-
 local table = require('table')
 
 local readline = require('readline')
diff --git a/impls/lua/stepA_mal.lua b/impls/lua/stepA_mal.lua
old mode 100755
new mode 100644
index 242b1cdda4..76f614966e
--- a/impls/lua/stepA_mal.lua
+++ b/impls/lua/stepA_mal.lua
@@ -1,5 +1,3 @@
-#!/usr/bin/env lua
-
 local table = require('table')
 
 package.path = '../lua/?.lua;' .. package.path
diff --git a/impls/make/reader.mk b/impls/make/reader.mk
old mode 100755
new mode 100644
diff --git a/impls/make/run b/impls/make/run
index 43b9344665..bfbcc4447e 100755
--- a/impls/make/run
+++ b/impls/make/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec make --no-print-directory -f $(dirname $0)/${STEP:-stepA_mal}.mk "${@}"
+#!/bin/sh
+set -Cefu
+exec make --no-print-directory -f ${STEP:-stepA_mal}.mk "$@"
diff --git a/impls/mal/run b/impls/mal/run
index 3bf6b5b09c..f9ac1907bc 100755
--- a/impls/mal/run
+++ b/impls/mal/run
@@ -1,9 +1,15 @@
-#!/usr/bin/env bash
+#!/bin/sh
+set -Cefu
 MAL_FILE=../mal/${STEP:-stepA_mal}.mal
 export STEP=stepA_mal # force MAL_IMPL to use stepA
-case ${MAL_IMPL} in
-*-mal)
-    MAL_IMPL=${MAL_IMPL%%-mal}
-    MAL_FILE="../mal/stepA_mal.mal ${MAL_FILE}" ;;
+impl=${MAL_IMPL:-js}
+case $impl in
+    *-mal)
+        cd ../${impl%-mal}
+        exec ./run ../mal/stepA_mal.mal $MAL_FILE "$@"
+        ;;
+    *)
+        cd ../$impl
+        exec ./run $MAL_FILE "$@"
+        ;;
 esac
-exec ./../${MAL_IMPL:-js}/run ${MAL_FILE} "${@}"
diff --git a/impls/matlab/run b/impls/matlab/run
index 332c5903de..34d12fa2ba 100755
--- a/impls/matlab/run
+++ b/impls/matlab/run
@@ -1,21 +1,20 @@
 #!/bin/sh
+set -Cefu
 
-args=
 for x; do
-    args="$args${args:+, }'$x'"
+    args="${args:+$args, }'$x'"
 done
+prompt="${STEP:-stepA_mal}(${args:-});quit;"
 
-case "$matlab_MODE" in
+case ${matlab_MODE:-octave} in
     matlab)
-        options='-nodisplay -nosplash -nodesktop -nojvm -r'
+        exec matlab -nodisplay -nosplash -nodesktop -nojvm -r "$prompt"
         ;;
     octave)
-        options='-q --no-gui --no-history --eval'
+        exec octave -q --no-gui --no-history --eval "$prompt"
         ;;
     *)
         echo "Bad matlab_MODE: $matlab_MODE"
         exit 1
         ;;
 esac
-
-exec $matlab_MODE $options "${STEP:-stepA_mal}($args);quit;"
diff --git a/impls/miniMAL/run b/impls/miniMAL/run
index 5fe9482d6e..824b708851 100755
--- a/impls/miniMAL/run
+++ b/impls/miniMAL/run
@@ -1,3 +1,3 @@
-#!/usr/bin/env bash
-cd $(dirname $0)
-exec miniMAL ./${STEP:-stepA_mal}.json "${@}"
+#!/bin/sh
+set -Cefu
+exec miniMAL ${STEP:-stepA_mal}.json "$@"
diff --git a/impls/nasm/run b/impls/nasm/run
index 016cc72d79..5ffd062744 100755
--- a/impls/nasm/run
+++ b/impls/nasm/run
@@ -1,3 +1,3 @@
-#!/usr/bin/env bash
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
-
+#!/bin/sh
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
diff --git a/impls/nim/run b/impls/nim/run
index 6efdc3de32..5ffd062744 100755
--- a/impls/nim/run
+++ b/impls/nim/run
@@ -1,2 +1,3 @@
 #!/bin/sh
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
diff --git a/impls/objc/run b/impls/objc/run
index c66c2b81dc..5ffd062744 100755
--- a/impls/objc/run
+++ b/impls/objc/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
+#!/bin/sh
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
diff --git a/impls/objpascal/run b/impls/objpascal/run
index c66c2b81dc..5ffd062744 100755
--- a/impls/objpascal/run
+++ b/impls/objpascal/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
+#!/bin/sh
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
diff --git a/impls/ocaml/run b/impls/ocaml/run
index 6efdc3de32..5ffd062744 100755
--- a/impls/ocaml/run
+++ b/impls/ocaml/run
@@ -1,2 +1,3 @@
 #!/bin/sh
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
diff --git a/impls/perl/run b/impls/perl/run
index 4f255fe5fe..88118dc06b 100755
--- a/impls/perl/run
+++ b/impls/perl/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec perl $(dirname $0)/${STEP:-stepA_mal}.pl "${@}"
+#!/bin/sh
+set -Cefu
+exec perl ${STEP:-stepA_mal}.pl ${RAW:+--raw} "$@"
diff --git a/impls/perl/step0_repl.pl b/impls/perl/step0_repl.pl
index 2947178df3..a0018328a5 100644
--- a/impls/perl/step0_repl.pl
+++ b/impls/perl/step0_repl.pl
@@ -1,5 +1,3 @@
-#!/usr/bin/perl
-
 use strict;
 use warnings;
 use File::Basename 'dirname';
@@ -34,7 +32,7 @@ sub REP {
 }
 
 # Command line arguments
-if ( $ARGV[0] eq '--raw' ) {
+if ( @ARGV and  $ARGV[0] eq '--raw' ) {
     set_rl_mode('raw');
     shift @ARGV;
 }
diff --git a/impls/perl/step1_read_print.pl b/impls/perl/step1_read_print.pl
index 43f2d82fcf..36f1bd92e9 100644
--- a/impls/perl/step1_read_print.pl
+++ b/impls/perl/step1_read_print.pl
@@ -1,5 +1,3 @@
-#!/usr/bin/perl
-
 use strict;
 use warnings;
 use File::Basename 'dirname';
@@ -36,7 +34,7 @@ sub REP {
 }
 
 # Command line arguments
-if ( $ARGV[0] eq '--raw' ) {
+if ( @ARGV and  $ARGV[0] eq '--raw' ) {
     set_rl_mode('raw');
     shift @ARGV;
 }
diff --git a/impls/perl/step2_eval.pl b/impls/perl/step2_eval.pl
index 23bccdc69f..6ed7b5b3c7 100644
--- a/impls/perl/step2_eval.pl
+++ b/impls/perl/step2_eval.pl
@@ -1,5 +1,3 @@
-#!/usr/bin/perl
-
 use strict;
 use warnings;
 use File::Basename 'dirname';
@@ -63,7 +61,7 @@ sub REP {
 }
 
 # Command line arguments
-if ( $ARGV[0] eq '--raw' ) {
+if ( @ARGV and  $ARGV[0] eq '--raw' ) {
     set_rl_mode('raw');
     shift @ARGV;
 }
diff --git a/impls/perl/step3_env.pl b/impls/perl/step3_env.pl
index 9b09031d8a..8add028df0 100644
--- a/impls/perl/step3_env.pl
+++ b/impls/perl/step3_env.pl
@@ -1,5 +1,3 @@
-#!/usr/bin/perl
-
 use strict;
 use warnings;
 use File::Basename 'dirname';
@@ -93,7 +91,7 @@ sub REP {
 }
 
 # Command line arguments
-if ( $ARGV[0] eq '--raw' ) {
+if ( @ARGV and  $ARGV[0] eq '--raw' ) {
     set_rl_mode('raw');
     shift @ARGV;
 }
diff --git a/impls/perl/step4_if_fn_do.pl b/impls/perl/step4_if_fn_do.pl
index df4b825302..b4cc282aca 100644
--- a/impls/perl/step4_if_fn_do.pl
+++ b/impls/perl/step4_if_fn_do.pl
@@ -1,5 +1,3 @@
-#!/usr/bin/perl
-
 use strict;
 use warnings;
 use File::Basename 'dirname';
@@ -124,7 +122,7 @@ sub REP {
 }
 
 # Command line arguments
-if ( $ARGV[0] eq '--raw' ) {
+if ( @ARGV and $ARGV[0] eq '--raw' ) {
     set_rl_mode('raw');
     shift @ARGV;
 }
diff --git a/impls/perl/step5_tco.pl b/impls/perl/step5_tco.pl
index 7d2460de36..de59963b0b 100644
--- a/impls/perl/step5_tco.pl
+++ b/impls/perl/step5_tco.pl
@@ -1,5 +1,3 @@
-#!/usr/bin/perl
-
 use strict;
 use warnings FATAL => 'recursion';
 use File::Basename 'dirname';
@@ -134,7 +132,7 @@ sub REP {
 }
 
 # Command line arguments
-if ( $ARGV[0] eq '--raw' ) {
+if ( @ARGV and $ARGV[0] eq '--raw' ) {
     set_rl_mode('raw');
     shift @ARGV;
 }
diff --git a/impls/perl/step6_file.pl b/impls/perl/step6_file.pl
index e0eca83ec5..ce6c496fc0 100644
--- a/impls/perl/step6_file.pl
+++ b/impls/perl/step6_file.pl
@@ -1,5 +1,3 @@
-#!/usr/bin/perl
-
 use strict;
 use warnings FATAL => 'recursion';
 use File::Basename 'dirname';
@@ -134,7 +132,7 @@ sub REP {
 }
 
 # Command line arguments
-if ( $ARGV[0] eq '--raw' ) {
+if ( @ARGV and $ARGV[0] eq '--raw' ) {
     set_rl_mode('raw');
     shift @ARGV;
 }
diff --git a/impls/perl/step7_quote.pl b/impls/perl/step7_quote.pl
index ceee9c894f..6042b83535 100644
--- a/impls/perl/step7_quote.pl
+++ b/impls/perl/step7_quote.pl
@@ -1,5 +1,3 @@
-#!/usr/bin/perl
-
 use strict;
 use warnings FATAL => 'recursion';
 use File::Basename 'dirname';
@@ -187,7 +185,7 @@ sub REP {
 }
 
 # Command line arguments
-if ( $ARGV[0] eq '--raw' ) {
+if ( @ARGV and $ARGV[0] eq '--raw' ) {
     set_rl_mode('raw');
     shift @ARGV;
 }
diff --git a/impls/perl/step8_macros.pl b/impls/perl/step8_macros.pl
index aee1bb8274..75c040a2f8 100644
--- a/impls/perl/step8_macros.pl
+++ b/impls/perl/step8_macros.pl
@@ -1,5 +1,3 @@
-#!/usr/bin/perl
-
 use strict;
 use warnings FATAL => 'recursion';
 use File::Basename 'dirname';
@@ -198,7 +196,7 @@ sub REP {
 }
 
 # Command line arguments
-if ( $ARGV[0] eq '--raw' ) {
+if ( @ARGV and $ARGV[0] eq '--raw' ) {
     set_rl_mode('raw');
     shift @ARGV;
 }
diff --git a/impls/perl/step9_try.pl b/impls/perl/step9_try.pl
index 3612fba99d..c3311d1ed6 100644
--- a/impls/perl/step9_try.pl
+++ b/impls/perl/step9_try.pl
@@ -1,5 +1,3 @@
-#!/usr/bin/perl
-
 use strict;
 use warnings FATAL => 'recursion';
 use File::Basename 'dirname';
@@ -221,7 +219,7 @@ sub REP {
 }
 
 # Command line arguments
-if ( $ARGV[0] eq '--raw' ) {
+if ( @ARGV and $ARGV[0] eq '--raw' ) {
     set_rl_mode('raw');
     shift @ARGV;
 }
diff --git a/impls/perl/stepA_mal.pl b/impls/perl/stepA_mal.pl
index e48046d504..698f9fb148 100644
--- a/impls/perl/stepA_mal.pl
+++ b/impls/perl/stepA_mal.pl
@@ -1,5 +1,3 @@
-#!/usr/bin/perl
-
 use strict;
 use warnings FATAL => 'recursion';
 use File::Basename 'dirname';
@@ -221,7 +219,7 @@ sub REP {
 }
 
 # Command line arguments
-if ( $ARGV[0] eq '--raw' ) {
+if ( @ARGV and $ARGV[0] eq '--raw' ) {
     set_rl_mode('raw');
     shift @ARGV;
 }
diff --git a/impls/perl6/run b/impls/perl6/run
index 80cb92b34b..8d8e369eed 100755
--- a/impls/perl6/run
+++ b/impls/perl6/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec perl6 $(dirname $0)/${STEP:-stepA_mal}.pl "${@}"
+#!/bin/sh
+set -Cefu
+exec perl6 ${STEP:-stepA_mal}.pl "$@"
diff --git a/impls/php/run b/impls/php/run
index daf97f93c0..d2f262bc2b 100755
--- a/impls/php/run
+++ b/impls/php/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec php $(dirname $0)/${STEP:-stepA_mal}.php "${@}"
+#!/bin/sh
+set -Cefu
+exec php ${STEP:-stepA_mal}.php "$@"
diff --git a/impls/php/tests/stepA_mal.mal b/impls/php/tests/stepA_mal.mal
index de459cdbcf..3a873c0440 100644
--- a/impls/php/tests/stepA_mal.mal
+++ b/impls/php/tests/stepA_mal.mal
@@ -37,7 +37,7 @@
 ;; testing superglobal variable access
 
 (get php/_SERVER "PHP_SELF")
-;=>"../php/stepA_mal.php"
+;=>"stepA_mal.php"
 
 ;; testing PHP constants access
 
diff --git a/impls/picolisp/run b/impls/picolisp/run
index a7f77da3fd..7e5ffa8b30 100755
--- a/impls/picolisp/run
+++ b/impls/picolisp/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec pil $(dirname $0)/${STEP:-stepA_mal}.l - "${@}"
+#!/bin/sh
+set -Cefu
+exec pil ${STEP:-stepA_mal}.l - "$@"
diff --git a/impls/pike/run b/impls/pike/run
index 1281d967de..bb8b2b35ee 100755
--- a/impls/pike/run
+++ b/impls/pike/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec pike $(dirname $0)/${STEP:-stepA_mal}.pike "${@}"
+#!/bin/sh
+set -Cefu
+exec pike ${STEP:-stepA_mal}.pike "$@"
diff --git a/impls/plpgsql/init.sql b/impls/plpgsql/init.sql
old mode 100755
new mode 100644
diff --git a/impls/plpgsql/run b/impls/plpgsql/run
index a16184e01a..b4237611be 100755
--- a/impls/plpgsql/run
+++ b/impls/plpgsql/run
@@ -1,2 +1,75 @@
 #!/usr/bin/env bash
-exec $(dirname $0)/wrap.sh $(dirname $0)/${STEP:-stepA_mal}.sql "${@}"
+step=${STEP:-stepA_mal}.sql
+
+RL_HISTORY_FILE=${HOME}/.mal-history
+SKIP_INIT="${SKIP_INIT:-}"
+PSQL_USER="${PSQL_USER:-postgres}"
+
+PSQL="psql -q -t -A -v ON_ERROR_STOP=1 ${PSQL_USER:+-U ${PSQL_USER}}"
+[ "${DEBUG}" ] || PSQL="${PSQL} -v VERBOSITY=terse"
+
+# If mal DB is not there, force create of it
+dbcheck=$(${PSQL} -c "select 1 from pg_database where datname='mal'")
+[ -z "${dbcheck}" ] && SKIP_INIT=
+
+STDOUT_PID= STDIN_PID=
+cleanup () {
+    trap - TERM QUIT INT EXIT
+    # Make sure input stream is closed. Input subprocess will do this
+    # for normal terminal input but in the runtest.py case it does not
+    # get a chance.
+    ${PSQL} -dmal -c "SELECT io.close(0);" > /dev/null
+    [ "${STDIN_PID}" ] && kill ${STDIN_PID} 2>/dev/null
+}
+
+# Load the SQL code
+trap "cleanup" TERM QUIT INT EXIT
+${PSQL} -tc "SELECT 1 FROM pg_database WHERE datname = 'mal'" \
+    | grep -q 1 || ${PSQL} -c "CREATE DATABASE mal"
+#[ "${SKIP_INIT}" ] || ${PSQL} -dmal -f $step > /dev/null
+[ "${SKIP_INIT}" ] || ${PSQL} -dmal -f $step
+
+${PSQL} -dmal -c "SELECT io.open(0); SELECT io.open(1);" > /dev/null
+
+# Stream from table to stdout
+(
+while true; do
+    out="$(${PSQL} -dmal -c "SELECT io.read_or_error(1)" 2>/dev/null)" || break
+    echo "${out}"
+done
+) &
+STDOUT_PID=$!
+
+# Perform readline input into stream table when requested
+(
+[ -r ${RL_HISTORY_FILE} ] && history -r ${RL_HISTORY_FILE}
+while true; do
+    prompt=$(${PSQL} -dmal \
+        -c "SELECT io.wait_rl_prompt(0);" 2>/dev/null) || break
+    IFS= read -u 0 -r -e -p "${prompt}" line || break
+    if [ "${line}" ]; then
+        history -s -- "${line}"        # add to history
+        history -a ${RL_HISTORY_FILE}  # save history to file
+    fi
+
+    ${PSQL} -dmal -v arg="${line}" \
+        -f <(echo "SELECT io.writeline(:'arg', 0);") >/dev/null || break
+done
+${PSQL} -dmal -c "SELECT io.close(0);" > /dev/null
+) <&0 >&1 &
+STDIN_PID=$!
+
+res=0
+if [ $# -gt 0 ]; then
+    # If there are command line arguments then run a command and exit
+    args=$(for a in "$@"; do echo -n "\"$a\" "; done)
+    ${PSQL} -dmal -v args="(${args})" \
+        -f <(echo "SELECT mal.MAIN('$(pwd)', :'args');") > /dev/null
+    res=$?
+else
+    # Start main loop in the background
+    ${PSQL} -dmal -c "SELECT mal.MAIN('$(pwd)');" > /dev/null
+    res=$?
+fi
+wait ${STDOUT_PID}
+exit ${res}
diff --git a/impls/plpgsql/wrap.sh b/impls/plpgsql/wrap.sh
deleted file mode 100755
index e14c072d6a..0000000000
--- a/impls/plpgsql/wrap.sh
+++ /dev/null
@@ -1,75 +0,0 @@
-#!/usr/bin/env bash
-
-RL_HISTORY_FILE=${HOME}/.mal-history
-SKIP_INIT="${SKIP_INIT:-}"
-PSQL_USER="${PSQL_USER:-postgres}"
-
-PSQL="psql -q -t -A -v ON_ERROR_STOP=1 ${PSQL_USER:+-U ${PSQL_USER}}"
-[ "${DEBUG}" ] || PSQL="${PSQL} -v VERBOSITY=terse"
-
-# If mal DB is not there, force create of it
-dbcheck=$(${PSQL} -c "select 1 from pg_database where datname='mal'")
-[ -z "${dbcheck}" ] && SKIP_INIT=
-
-STDOUT_PID= STDIN_PID=
-cleanup () {
-    trap - TERM QUIT INT EXIT
-    # Make sure input stream is closed. Input subprocess will do this
-    # for normal terminal input but in the runtest.py case it does not
-    # get a chance.
-    ${PSQL} -dmal -c "SELECT io.close(0);" > /dev/null
-    [ "${STDIN_PID}" ] && kill ${STDIN_PID} 2>/dev/null
-}
-
-# Load the SQL code
-trap "cleanup" TERM QUIT INT EXIT
-${PSQL} -tc "SELECT 1 FROM pg_database WHERE datname = 'mal'" \
-    | grep -q 1 || ${PSQL} -c "CREATE DATABASE mal"
-#[ "${SKIP_INIT}" ] || ${PSQL} -dmal -f $1 > /dev/null
-[ "${SKIP_INIT}" ] || ${PSQL} -dmal -f $1
-
-${PSQL} -dmal -c "SELECT io.open(0); SELECT io.open(1);" > /dev/null
-
-# Stream from table to stdout
-(
-while true; do
-    out="$(${PSQL} -dmal -c "SELECT io.read_or_error(1)" 2>/dev/null)" || break
-    echo "${out}"
-done
-) &
-STDOUT_PID=$!
-
-# Perform readline input into stream table when requested
-(
-[ -r ${RL_HISTORY_FILE} ] && history -r ${RL_HISTORY_FILE}
-while true; do
-    prompt=$(${PSQL} -dmal \
-        -c "SELECT io.wait_rl_prompt(0);" 2>/dev/null) || break
-    IFS= read -u 0 -r -e -p "${prompt}" line || break
-    if [ "${line}" ]; then
-        history -s -- "${line}"        # add to history
-        history -a ${RL_HISTORY_FILE}  # save history to file
-    fi
-
-    ${PSQL} -dmal -v arg="${line}" \
-        -f <(echo "SELECT io.writeline(:'arg', 0);") >/dev/null || break
-done
-${PSQL} -dmal -c "SELECT io.close(0);" > /dev/null
-) <&0 >&1 &
-STDIN_PID=$!
-
-res=0
-shift
-if [ $# -gt 0 ]; then
-    # If there are command line arguments then run a command and exit
-    args=$(for a in "$@"; do echo -n "\"$a\" "; done)
-    ${PSQL} -dmal -v args="(${args})" \
-        -f <(echo "SELECT mal.MAIN('$(pwd)', :'args');") > /dev/null
-    res=$?
-else
-    # Start main loop in the background
-    ${PSQL} -dmal -c "SELECT mal.MAIN('$(pwd)');" > /dev/null
-    res=$?
-fi
-wait ${STDOUT_PID}
-exit ${res}
diff --git a/impls/plsql/run b/impls/plsql/run
index a16184e01a..39f9d037c1 100755
--- a/impls/plsql/run
+++ b/impls/plsql/run
@@ -1,2 +1,122 @@
 #!/usr/bin/env bash
-exec $(dirname $0)/wrap.sh $(dirname $0)/${STEP:-stepA_mal}.sql "${@}"
+step=${STEP:-stepA_mal}.sql
+
+RL_HISTORY_FILE=${HOME}/.mal-history
+SKIP_INIT="${SKIP_INIT:-}"
+
+ORACLE_LOGON=${ORACLE_LOGON:-system/oracle}
+SQLPLUS="sqlplus -S ${ORACLE_LOGON}"
+
+FILE_PID=
+cleanup() {
+    trap - TERM QUIT INT EXIT
+    #echo cleanup: ${FILE_PID}
+    [ "${FILE_PID}" ] && kill ${FILE_PID}
+}
+trap "cleanup" TERM QUIT INT EXIT
+
+
+# Load the SQL code
+if [ -z "${SKIP_INIT}" ]; then
+    out=$(echo "" | ${SQLPLUS} @$step)
+    if echo "${out}" | grep -vs "^No errors.$" \
+        | grep -si error >/dev/null; then
+    #if echo "${out}"  | grep -si error >/dev/null; then
+        echo "${out}"
+        exit 1
+    fi
+fi
+
+# open I/O streams
+echo -e "BEGIN io.open(0); io.open(1); END;\n/" \
+    | ${SQLPLUS} >/dev/null
+
+# Stream from table to stdout
+(
+while true; do
+    out="$(echo "SELECT io.read(1) FROM dual;" \
+        | ${SQLPLUS} 2>/dev/null)" || break
+    #echo "out: [${out}] (${#out})"
+    echo "${out}"
+done
+) &
+STDOUT_PID=$!
+
+# Perform readline input into stream table when requested
+(
+[ -r ${RL_HISTORY_FILE} ] && history -r ${RL_HISTORY_FILE}
+while true; do
+    prompt=$(echo "SELECT io.wait_rl_prompt(0) FROM dual;" \
+        | ${SQLPLUS} 2>/dev/null) || break
+    # Prompt is returned single-quoted because sqlplus trims trailing
+    # whitespace. Remove the single quotes from the beginning and end:
+    prompt=${prompt%\'}
+    prompt=${prompt#\'}
+    #echo "prompt: [${prompt}]"
+
+    IFS= read -u 0 -r -e -p "${prompt}" line || break
+    if [ "${line}" ]; then
+        history -s -- "${line}"        # add to history
+        history -a ${RL_HISTORY_FILE}  # save history to file
+    fi
+
+    # Escape (double) single quotes per SQL norm
+    line=${line//\'/\'\'}
+    #echo "line: [${line}]"
+    ( echo -n "BEGIN io.writeline('${line}', 0); END;";
+      echo -en "\n/" ) \
+        | ${SQLPLUS} >/dev/null || break
+done
+echo -e "BEGIN io.close(0); END;\n/" \
+    | ${SQLPLUS} > /dev/null
+) <&0 >&1 &
+
+
+# File read if requested
+(
+while true; do
+    files="$(echo "SELECT path FROM file_io WHERE in_or_out = 'in';" \
+        | ${SQLPLUS} 2>/dev/null \
+        | grep -v "^no rows selected")" || break
+    for f in ${files}; do
+        if [ ! -r ${f} ]; then
+            echo "UPDATE file_io SET error = 'Cannot read ''${f}''' WHERE path = '${f}' AND in_or_out = 'in';" \
+                | ${SQLPLUS} >/dev/null
+            continue;
+        fi
+        IFS= read -rd '' content < "${f}"
+        # sqlplus limits lines to 2499 characters so split the update
+        # into chunks of the file ORed together over multiple lines
+        query="UPDATE file_io SET data = TO_CLOB('')"
+        while [ -n "${content}" ]; do
+            chunk="${content:0:2000}"
+            content="${content:${#chunk}}"
+            chunk="${chunk//\'/\'\'}"
+            chunk="${chunk//$'\n'/\\n}"
+            query="${query}"$'\n'"    || TO_CLOB('${chunk}')"
+        done
+        query="${query}"$'\n'" WHERE path = '${f}' AND in_or_out = 'in';"
+        echo "${query}" | ${SQLPLUS} > /dev/null
+        #echo "file read: ${f}: ${?}"
+    done
+    sleep 1
+done
+) &
+FILE_PID=$!
+
+res=0
+if [ $# -gt 0 ]; then
+    # If there are command line arguments then run a command and exit
+    args=$(for a in "$@"; do echo -n "\"$a\" "; done)
+    echo -e "SELECT mal.MAIN('(${args})') FROM dual;" \
+        | ${SQLPLUS} > /dev/null
+    res=$?
+else
+    # Start main loop in the background
+    echo "SELECT mal.MAIN() FROM dual;" \
+        | ${SQLPLUS} > /dev/null
+    res=$?
+fi
+# Wait for output to flush
+wait ${STDOUT_PID}
+exit ${res}
diff --git a/impls/plsql/wrap.sh b/impls/plsql/wrap.sh
deleted file mode 100755
index c106ecb98b..0000000000
--- a/impls/plsql/wrap.sh
+++ /dev/null
@@ -1,122 +0,0 @@
-#!/usr/bin/env bash
-
-RL_HISTORY_FILE=${HOME}/.mal-history
-SKIP_INIT="${SKIP_INIT:-}"
-
-ORACLE_LOGON=${ORACLE_LOGON:-system/oracle}
-SQLPLUS="sqlplus -S ${ORACLE_LOGON}"
-
-FILE_PID=
-cleanup() {
-    trap - TERM QUIT INT EXIT
-    #echo cleanup: ${FILE_PID}
-    [ "${FILE_PID}" ] && kill ${FILE_PID}
-}
-trap "cleanup" TERM QUIT INT EXIT
-
-
-# Load the SQL code
-if [ -z "${SKIP_INIT}" ]; then
-    out=$(echo "" | ${SQLPLUS} @$1)
-    if echo "${out}" | grep -vs "^No errors.$" \
-        | grep -si error >/dev/null; then
-    #if echo "${out}"  | grep -si error >/dev/null; then
-        echo "${out}"
-        exit 1
-    fi
-fi
-
-# open I/O streams
-echo -e "BEGIN io.open(0); io.open(1); END;\n/" \
-    | ${SQLPLUS} >/dev/null
-
-# Stream from table to stdout
-(
-while true; do
-    out="$(echo "SELECT io.read(1) FROM dual;" \
-        | ${SQLPLUS} 2>/dev/null)" || break
-    #echo "out: [${out}] (${#out})"
-    echo "${out}"
-done
-) &
-STDOUT_PID=$!
-
-# Perform readline input into stream table when requested
-(
-[ -r ${RL_HISTORY_FILE} ] && history -r ${RL_HISTORY_FILE}
-while true; do
-    prompt=$(echo "SELECT io.wait_rl_prompt(0) FROM dual;" \
-        | ${SQLPLUS} 2>/dev/null) || break
-    # Prompt is returned single-quoted because sqlplus trims trailing
-    # whitespace. Remove the single quotes from the beginning and end:
-    prompt=${prompt%\'}
-    prompt=${prompt#\'}
-    #echo "prompt: [${prompt}]"
-
-    IFS= read -u 0 -r -e -p "${prompt}" line || break
-    if [ "${line}" ]; then
-        history -s -- "${line}"        # add to history
-        history -a ${RL_HISTORY_FILE}  # save history to file
-    fi
-
-    # Escape (double) single quotes per SQL norm
-    line=${line//\'/\'\'}
-    #echo "line: [${line}]"
-    ( echo -n "BEGIN io.writeline('${line}', 0); END;";
-      echo -en "\n/" ) \
-        | ${SQLPLUS} >/dev/null || break
-done
-echo -e "BEGIN io.close(0); END;\n/" \
-    | ${SQLPLUS} > /dev/null
-) <&0 >&1 &
-
-
-# File read if requested
-(
-while true; do
-    files="$(echo "SELECT path FROM file_io WHERE in_or_out = 'in';" \
-        | ${SQLPLUS} 2>/dev/null \
-        | grep -v "^no rows selected")" || break
-    for f in ${files}; do
-        if [ ! -r ${f} ]; then
-            echo "UPDATE file_io SET error = 'Cannot read ''${f}''' WHERE path = '${f}' AND in_or_out = 'in';" \
-                | ${SQLPLUS} >/dev/null
-            continue;
-        fi
-        IFS= read -rd '' content < "${f}"
-        # sqlplus limits lines to 2499 characters so split the update
-        # into chunks of the file ORed together over multiple lines
-        query="UPDATE file_io SET data = TO_CLOB('')"
-        while [ -n "${content}" ]; do
-            chunk="${content:0:2000}"
-            content="${content:${#chunk}}"
-            chunk="${chunk//\'/\'\'}"
-            chunk="${chunk//$'\n'/\\n}"
-            query="${query}"$'\n'"    || TO_CLOB('${chunk}')"
-        done
-        query="${query}"$'\n'" WHERE path = '${f}' AND in_or_out = 'in';"
-        echo "${query}" | ${SQLPLUS} > /dev/null
-        #echo "file read: ${f}: ${?}"
-    done
-    sleep 1
-done
-) &
-FILE_PID=$!
-
-res=0
-shift
-if [ $# -gt 0 ]; then
-    # If there are command line arguments then run a command and exit
-    args=$(for a in "$@"; do echo -n "\"$a\" "; done)
-    echo -e "SELECT mal.MAIN('(${args})') FROM dual;" \
-        | ${SQLPLUS} > /dev/null
-    res=$?
-else
-    # Start main loop in the background
-    echo "SELECT mal.MAIN() FROM dual;" \
-        | ${SQLPLUS} > /dev/null
-    res=$?
-fi
-# Wait for output to flush
-wait ${STDOUT_PID}
-exit ${res}
diff --git a/impls/powershell/run b/impls/powershell/run
index 7adde42817..4687eac282 100755
--- a/impls/powershell/run
+++ b/impls/powershell/run
@@ -1,2 +1,3 @@
 #!/bin/sh
-exec powershell $(dirname $0)/${STEP:-stepA_mal}.ps1 "${@}"
+set -Cefu
+exec powershell ./${STEP:-stepA_mal}.ps1 "$@"
diff --git a/impls/prolog/run b/impls/prolog/run
index 6a9b5f1fe4..fa8ca18ff3 100755
--- a/impls/prolog/run
+++ b/impls/prolog/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec swipl $(dirname $0)/${STEP:-stepA_mal}.pl "${@}"
+#!/bin/sh
+set -Cefu
+exec swipl ${STEP:-stepA_mal}.pl "$@"
diff --git a/impls/ps/run b/impls/ps/run
index a961d13c7f..2887396e2e 100755
--- a/impls/ps/run
+++ b/impls/ps/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec gs -q -I$(dirname $0) -dNOSAFER -dNODISPLAY -- $(dirname $0)/${STEP:-stepA_mal}.ps "${@}"
+#!/bin/sh
+set -Cefu
+exec gs -q -I. -dNOSAFER -dNODISPLAY -- ${STEP:-stepA_mal}.ps "$@"
diff --git a/impls/purs/Makefile b/impls/purs/Makefile
index 5de690be1b..bfa9227cfa 100644
--- a/impls/purs/Makefile
+++ b/impls/purs/Makefile
@@ -1,35 +1,16 @@
-BINS = step0_repl.js step1_read_print.js step2_eval.js step3_env.js \
-       step4_if_fn_do.js step5_tco.js step6_file.js step7_quote.js \
-       step8_macros.js step9_try.js stepA_mal.js
-
-OTHER_SRCS = src/Readline.js src/Readline.purs src/Types.purs src/Reader.purs \
-             src/Printer.purs src/Env.purs src/Core.purs
-
+sources    := $(wildcard src/*)
+BIN_SRCS   := $(filter     src/step%.purs,$(sources))
+OTHER_SRCS := $(filter-out src/step%.purs,$(sources))
+BINS       := $(BIN_SRCS:src/step%.purs=step%.js)
 
 all: $(BINS)
 
-$(BINS): %.js: src/%.purs $(OTHER_SRCS) node_modules/readline-sync
-	spago bundle-app --main $($(<:src/%=%)) --to $@
-
+$(BINS): step%.js: src/step%.purs $(OTHER_SRCS) node_modules/readline-sync
+	spago bundle-app --main Mal.Step$(firstword $(subst _, ,$*)) --to $@
 
 node_modules/readline-sync:
 	npm install
 
-
-#####################
-
-step0_repl.purs = Mal.Step0
-step1_read_print.purs = Mal.Step1
-step2_eval.purs = Mal.Step2
-step3_env.purs = Mal.Step3
-step4_if_fn_do.purs = Mal.Step4
-step5_tco.purs = Mal.Step5
-step6_file.purs = Mal.Step6
-step7_quote.purs = Mal.Step7
-step8_macros.purs = Mal.Step8
-step9_try.purs = Mal.Step9
-stepA_mal.purs = Mal.StepA
-
-
 clean:
-	rm -rf step*.js output/*
\ No newline at end of file
+	rm -f $(BINS)
+	rm -fr output/
diff --git a/impls/purs/run b/impls/purs/run
index 510f226881..d1135e76d4 100755
--- a/impls/purs/run
+++ b/impls/purs/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec node $(dirname $0)/${STEP:-stepA_mal}.js "${@}"
\ No newline at end of file
+#!/bin/sh
+set -Cefu
+exec node ${STEP:-stepA_mal}.js "$@"
diff --git a/impls/python2/run b/impls/python2/run
index 095e1963d0..69c9dc7644 100755
--- a/impls/python2/run
+++ b/impls/python2/run
@@ -1,2 +1,3 @@
 #!/bin/sh
-exec python2 $(dirname $0)/${STEP:-stepA_mal}.py "${@}"
+set -Cefu
+exec python2 ${STEP:-stepA_mal}.py "$@"
diff --git a/impls/python3/run b/impls/python3/run
index 1e7632cd57..e57219fcae 100755
--- a/impls/python3/run
+++ b/impls/python3/run
@@ -1,2 +1,3 @@
 #!/bin/sh
-exec python3 $(dirname $0)/${STEP:-stepA_mal}.py "${@}"
+set -Cefu
+exec python3 ${STEP:-stepA_mal}.py "$@"
diff --git a/impls/r/run b/impls/r/run
index 916876f09d..3d8166379b 100755
--- a/impls/r/run
+++ b/impls/r/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec Rscript $(dirname $0)/${STEP:-stepA_mal}.r "${@}"
+#!/bin/sh
+set -Cefu
+exec Rscript ${STEP:-stepA_mal}.r "$@"
diff --git a/impls/racket/run b/impls/racket/run
index fa0719bdce..72658cfba8 100755
--- a/impls/racket/run
+++ b/impls/racket/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec racket $(dirname $0)/${STEP:-stepA_mal}.rkt "${@}"
+#!/bin/sh
+set -Cefu
+exec racket ${STEP:-stepA_mal}.rkt "$@"
diff --git a/impls/racket/step0_repl.rkt b/impls/racket/step0_repl.rkt
old mode 100755
new mode 100644
index 643d132fa2..8cd3913fa9
--- a/impls/racket/step0_repl.rkt
+++ b/impls/racket/step0_repl.rkt
@@ -1,4 +1,3 @@
-#!/usr/bin/env racket
 #lang racket
 
 (require "readline.rkt" "types.rkt")
diff --git a/impls/racket/step1_read_print.rkt b/impls/racket/step1_read_print.rkt
old mode 100755
new mode 100644
index a5d8ac7761..53a64b4382
--- a/impls/racket/step1_read_print.rkt
+++ b/impls/racket/step1_read_print.rkt
@@ -1,4 +1,3 @@
-#!/usr/bin/env racket
 #lang racket
 
 (require "readline.rkt" "types.rkt" "reader.rkt" "printer.rkt")
diff --git a/impls/racket/step2_eval.rkt b/impls/racket/step2_eval.rkt
old mode 100755
new mode 100644
index 7ea1ce8f5d..08ac5a2ee6
--- a/impls/racket/step2_eval.rkt
+++ b/impls/racket/step2_eval.rkt
@@ -1,4 +1,3 @@
-#!/usr/bin/env racket
 #lang racket
 
 (require "types.rkt" "readline.rkt" "reader.rkt" "printer.rkt")
diff --git a/impls/racket/step3_env.rkt b/impls/racket/step3_env.rkt
old mode 100755
new mode 100644
index 8ecd818507..469e07fb8f
--- a/impls/racket/step3_env.rkt
+++ b/impls/racket/step3_env.rkt
@@ -1,4 +1,3 @@
-#!/usr/bin/env racket
 #lang racket
 
 (require "readline.rkt" "types.rkt" "reader.rkt" "printer.rkt"
diff --git a/impls/racket/step4_if_fn_do.rkt b/impls/racket/step4_if_fn_do.rkt
old mode 100755
new mode 100644
index 44af35c119..28a46b18e2
--- a/impls/racket/step4_if_fn_do.rkt
+++ b/impls/racket/step4_if_fn_do.rkt
@@ -1,4 +1,3 @@
-#!/usr/bin/env racket
 #lang racket
 
 (require "readline.rkt" "types.rkt" "reader.rkt" "printer.rkt"
diff --git a/impls/racket/step5_tco.rkt b/impls/racket/step5_tco.rkt
old mode 100755
new mode 100644
index 880e05ae5c..2d2f3defaf
--- a/impls/racket/step5_tco.rkt
+++ b/impls/racket/step5_tco.rkt
@@ -1,4 +1,3 @@
-#!/usr/bin/env racket
 #lang racket
 
 (require "readline.rkt" "types.rkt" "reader.rkt" "printer.rkt"
diff --git a/impls/racket/step6_file.rkt b/impls/racket/step6_file.rkt
old mode 100755
new mode 100644
index 6e1645bce9..783978ed61
--- a/impls/racket/step6_file.rkt
+++ b/impls/racket/step6_file.rkt
@@ -1,4 +1,3 @@
-#!/usr/bin/env racket
 #lang racket
 
 (require "readline.rkt" "types.rkt" "reader.rkt" "printer.rkt"
diff --git a/impls/racket/step7_quote.rkt b/impls/racket/step7_quote.rkt
old mode 100755
new mode 100644
index d9257f4889..f61aa7d000
--- a/impls/racket/step7_quote.rkt
+++ b/impls/racket/step7_quote.rkt
@@ -1,4 +1,3 @@
-#!/usr/bin/env racket
 #lang racket
 
 (require "readline.rkt" "types.rkt" "reader.rkt" "printer.rkt"
diff --git a/impls/racket/step8_macros.rkt b/impls/racket/step8_macros.rkt
old mode 100755
new mode 100644
index 864093047e..88a6d36567
--- a/impls/racket/step8_macros.rkt
+++ b/impls/racket/step8_macros.rkt
@@ -1,4 +1,3 @@
-#!/usr/bin/env racket
 #lang racket
 
 (require "readline.rkt" "types.rkt" "reader.rkt" "printer.rkt"
diff --git a/impls/racket/step9_try.rkt b/impls/racket/step9_try.rkt
old mode 100755
new mode 100644
index c8534d3b2b..ad42d983dc
--- a/impls/racket/step9_try.rkt
+++ b/impls/racket/step9_try.rkt
@@ -1,4 +1,3 @@
-#!/usr/bin/env racket
 #lang racket
 
 (require "readline.rkt" "types.rkt" "reader.rkt" "printer.rkt"
diff --git a/impls/racket/stepA_mal.rkt b/impls/racket/stepA_mal.rkt
old mode 100755
new mode 100644
index c94bb80137..83cb4d13aa
--- a/impls/racket/stepA_mal.rkt
+++ b/impls/racket/stepA_mal.rkt
@@ -1,4 +1,3 @@
-#!/usr/bin/env racket
 #lang racket
 
 (require "readline.rkt" "types.rkt" "reader.rkt" "printer.rkt"
diff --git a/impls/rexx/run b/impls/rexx/run
index b911329610..307605eaae 100755
--- a/impls/rexx/run
+++ b/impls/rexx/run
@@ -1,2 +1,3 @@
 #!/bin/sh
-exec rexx -a $(dirname $0)/${STEP:-stepA_mal}.rexxpp "${@}"
+set -Cefu
+exec rexx -a ${STEP:-stepA_mal}.rexxpp "$@"
diff --git a/impls/rpython/run b/impls/rpython/run
index c66c2b81dc..5ffd062744 100755
--- a/impls/rpython/run
+++ b/impls/rpython/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
+#!/bin/sh
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
diff --git a/impls/ruby.2/run b/impls/ruby.2/run
index 980db0d659..af3ef3ab4e 100755
--- a/impls/ruby.2/run
+++ b/impls/ruby.2/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec ruby $(dirname $0)/${STEP:-stepA_mal}.rb "${@}"
+#!/bin/sh
+set -Cefu
+exec ruby ${STEP:-stepA_mal}.rb "$@"
diff --git a/impls/ruby/run b/impls/ruby/run
index 980db0d659..af3ef3ab4e 100755
--- a/impls/ruby/run
+++ b/impls/ruby/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec ruby $(dirname $0)/${STEP:-stepA_mal}.rb "${@}"
+#!/bin/sh
+set -Cefu
+exec ruby ${STEP:-stepA_mal}.rb "$@"
diff --git a/impls/rust/run b/impls/rust/run
index d67524c747..46e9ab2269 100755
--- a/impls/rust/run
+++ b/impls/rust/run
@@ -1,2 +1,3 @@
 #!/bin/sh
-exec $(dirname $0)/target/release/${STEP:-stepA_mal} "${@}"
+set -Cefu
+exec target/release/${STEP:-stepA_mal} "$@"
diff --git a/impls/scala/run b/impls/scala/run
index eb06292ab5..57b25b1e65 100755
--- a/impls/scala/run
+++ b/impls/scala/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec java -classpath "$(dirname $0)/target/scala-2.11/mal.jar" "${STEP:-stepA_mal}" "$@"
+#!/bin/sh
+set -Cefu
+exec java -classpath target/scala-2.11/mal.jar ${STEP:-stepA_mal} "$@"
diff --git a/impls/scheme/run b/impls/scheme/run
index 8cfd055ae2..ab089dc050 100755
--- a/impls/scheme/run
+++ b/impls/scheme/run
@@ -1,26 +1,30 @@
-#!/usr/bin/env bash
-basedir=$(dirname $0)
+#!/bin/sh
+set -Cefu
 step=${STEP:-stepA_mal}
 
-if [[ -e /usr/share/kawa/lib/kawa.jar ]]; then
-    kawa=/usr/share/kawa/lib/kawa.jar
-elif [[ -e /usr/local/share/kawa/lib/kawa.jar ]]; then
-    kawa=/usr/local/share/kawa/lib/kawa.jar
-fi
-
-if [[ $(which sash 2>/dev/null) ]]; then
-    sagittarius=sash
-elif [[ $(which sagittarius 2>/dev/null) ]]; then
-    sagittarius=sagittarius
-fi
-
 case ${scheme_MODE:-chibi} in
-    chibi)       exec chibi-scheme -I$basedir $basedir/$step.scm      "${@}" ;;
-    kawa)        exec java -cp $kawa:$basedir/out $step               "${@}" ;;
-    gauche)      exec gosh -I$basedir $basedir/$step.scm              "${@}" ;;
-    chicken)     CHICKEN_REPOSITORY=$basedir/eggs exec $basedir/$step "${@}" ;;
-    sagittarius) exec $sagittarius -n -L$basedir $basedir/$step.scm   "${@}" ;;
-    cyclone)     exec $basedir/$step                                  "${@}" ;;
-    foment)      exec foment $basedir/$step.scm                       "${@}" ;;
-    *) echo "Invalid scheme_MODE: ${scheme_MODE}"; exit 2 ;;
+    chibi)       exec chibi-scheme $step.scm                         "$@" ;;
+    kawa)        if [ -e /usr/share/kawa/lib/kawa.jar ]; then
+                     kawa=/usr/share/kawa/lib/kawa.jar
+                  elif [ -e /usr/local/share/kawa/lib/kawa.jar ]; then
+                     kawa=/usr/local/share/kawa/lib/kawa.jar
+                 else
+                     echo >&2 'Failed to find kawa.jar.'
+                     exit 1
+                 fi
+                 exec java -cp $kawa:out $step                       "$@" ;;
+    gauche)      exec gosh -I. $step.scm                             "$@" ;;
+    chicken)     CHICKEN_REPOSITORY=eggs exec ./$step                "$@" ;;
+    sagittarius) if command -v sash >/dev/null 2>&1; then
+                     sagittarius=sash
+                 elif command -v sagittarius >/dev/null 2>&1; then
+                     sagittarius=sagittarius
+                 else
+                     echo >&2 'Failed to find sash or sagittarius.'
+                     exit 1
+                 fi
+                 exec $sagittarius -n -L. $step.scm                  "$@" ;;
+    cyclone)     exec ./$step                                        "$@" ;;
+    foment)      exec foment $step.scm                               "$@" ;;
+    *) echo "Invalid scheme_MODE: $scheme_MODE"; exit 2 ;;
 esac
diff --git a/impls/skew/run b/impls/skew/run
index 1148122a23..d1135e76d4 100755
--- a/impls/skew/run
+++ b/impls/skew/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec node $(dirname $0)/${STEP:-stepA_mal}.js "${@}"
+#!/bin/sh
+set -Cefu
+exec node ${STEP:-stepA_mal}.js "$@"
diff --git a/impls/sml/run b/impls/sml/run
index c66c2b81dc..5ffd062744 100755
--- a/impls/sml/run
+++ b/impls/sml/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
+#!/bin/sh
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
diff --git a/impls/swift3/run b/impls/swift3/run
index c66c2b81dc..5ffd062744 100755
--- a/impls/swift3/run
+++ b/impls/swift3/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
+#!/bin/sh
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
diff --git a/impls/swift4/run b/impls/swift4/run
index c66c2b81dc..5ffd062744 100755
--- a/impls/swift4/run
+++ b/impls/swift4/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
+#!/bin/sh
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
diff --git a/impls/swift6/run b/impls/swift6/run
index 8003dd69cb..5163410dfe 100755
--- a/impls/swift6/run
+++ b/impls/swift6/run
@@ -1,2 +1,3 @@
 #!/bin/sh
-exec $(dirname $0)/.build/${STEP:-stepA_mal} "${@}"
+set -Cefu
+exec .build/${STEP:-stepA_mal} "$@"
diff --git a/impls/tcl/run b/impls/tcl/run
index 700b5291b0..be3858ef90 100755
--- a/impls/tcl/run
+++ b/impls/tcl/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec tclsh $(dirname $0)/${STEP:-stepA_mal}.tcl ${RAW:+--raw} "${@}"
+#!/bin/sh
+set -Cefu
+exec tclsh ${STEP:-stepA_mal}.tcl ${RAW:+--raw} "$@"
diff --git a/impls/tests/run_argv_test.sh b/impls/tests/run_argv_test.sh
index e3682e4f9f..25859019ef 100755
--- a/impls/tests/run_argv_test.sh
+++ b/impls/tests/run_argv_test.sh
@@ -1,4 +1,5 @@
-#!/usr/bin/env bash
+#!/bin/sh
+set -Cefu
 
 #
 # Usage: run_argv_test.sh <command line arguments to run mal>
@@ -21,7 +22,7 @@ if [ -z "$1" ] ; then
   exit 1
 fi
 
-root="$(dirname $0)"
+root=../tests
 
 out="$( $@ $root/print_argv.mal aaa bbb ccc | tr -d '\r' )"
 assert_equal '("aaa" "bbb" "ccc")' "$out"
diff --git a/impls/ts/run b/impls/ts/run
index 1148122a23..d1135e76d4 100755
--- a/impls/ts/run
+++ b/impls/ts/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec node $(dirname $0)/${STEP:-stepA_mal}.js "${@}"
+#!/bin/sh
+set -Cefu
+exec node ${STEP:-stepA_mal}.js "$@"
diff --git a/impls/vala/run b/impls/vala/run
index c66c2b81dc..5ffd062744 100755
--- a/impls/vala/run
+++ b/impls/vala/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
+#!/bin/sh
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
diff --git a/impls/vb/run b/impls/vb/run
index 5c5642646f..8ea6fdbea1 100755
--- a/impls/vb/run
+++ b/impls/vb/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec mono $(dirname $0)/${STEP:-stepA_mal}.exe ${RAW:+--raw} "${@}"
+#!/bin/sh
+set -Cefu
+exec mono ${STEP:-stepA_mal}.exe ${RAW:+--raw} "$@"
diff --git a/impls/vbs/run b/impls/vbs/run
old mode 100644
new mode 100755
index 3c1aed2dd3..d225cb3a44
--- a/impls/vbs/run
+++ b/impls/vbs/run
@@ -1,4 +1,5 @@
-#!/usr/bin/env bash
+#!/bin/sh
+set -Cefu
 MAL_VBS_IMPL_NO_STDERR=1 MAL_VBS_IMPL_ECHO_STDIN=1 \
 WSLENV=MAL_VBS_IMPL_NO_STDERR/w:MAL_VBS_IMPL_ECHO_STDIN/w \
-cscript.exe -nologo "`wslpath -w "$(dirname $0)/${STEP:-stepA_mal}.vbs"`" "${@}"
\ No newline at end of file
+exec cscript.exe -nologo ${STEP:-stepA_mal}.vbs "$@"
diff --git a/impls/vhdl/Makefile b/impls/vhdl/Makefile
index e76b8e104a..5e9fe86a7d 100644
--- a/impls/vhdl/Makefile
+++ b/impls/vhdl/Makefile
@@ -32,4 +32,4 @@ $(BINS): %: %.o
 	if [ "$@" = "stepA_mal" ]; then mv stepa_mal $@; fi
 
 clean:
-	rm -f $(OBJS) $(BINS) $(OTHER_OBJS) work-obj93.cf mal
+	rm -f $(OBJS) $(BINS) $(OTHER_OBJS) work-obj93.cf mal vhdl_argv.tmp
diff --git a/impls/vhdl/run b/impls/vhdl/run
index ca50d3f82b..5201cee735 100755
--- a/impls/vhdl/run
+++ b/impls/vhdl/run
@@ -1,2 +1,13 @@
-#!/usr/bin/env bash
-exec $(dirname $0)/run_vhdl.sh $(dirname $0)/${STEP:-stepA_mal} "${@}"
+#!/bin/sh
+set -efu
+
+# ghdl doesn't allow passing command-line arguments to the VHDL program.  To
+# circumvent that, we write the command-line arguments as lines in
+# vhdl_argv.tmp, and read the content of that file at the beginning of the VHDL
+# program.
+
+for arg; do
+    echo "$arg"
+done > vhdl_argv.tmp
+
+exec ./${STEP:-stepA_mal}
diff --git a/impls/vhdl/run_vhdl.sh b/impls/vhdl/run_vhdl.sh
deleted file mode 100755
index 1cc8e3bf9f..0000000000
--- a/impls/vhdl/run_vhdl.sh
+++ /dev/null
@@ -1,21 +0,0 @@
-#!/usr/bin/env bash
-
-# ghdl doesn't allow passing command-line arguments to the VHDL program.  To
-# circumvent that, we write the command-line arguments as lines in
-# vhdl_argv.tmp, and read the content of that file at the beginning of the VHDL
-# program.
-
-cleanup() {
-    trap - TERM QUIT INT EXIT
-    rm -f vhdl_argv.tmp
-}
-trap "cleanup" TERM QUIT INT EXIT
-
-bin="$1"
-shift
-
-for arg in "$@" ; do
-    echo "$arg"
-done > vhdl_argv.tmp
-
-$bin
diff --git a/impls/vimscript/run b/impls/vimscript/run
index 007df20bdf..2cb7a320b4 100755
--- a/impls/vimscript/run
+++ b/impls/vimscript/run
@@ -1,3 +1,16 @@
-#!/usr/bin/env bash
-cd $(dirname $0)
-exec ./run_vimscript.sh ./${STEP:-stepA_mal}.vim "${@}"
+#!/bin/sh
+set -Cefu
+
+# Run Vim in ex mode (-e) and run the given script ($1) on startup. Our scripts
+# end with 'qall!' which causes actual Vim UI to never start up.
+#
+# Set environment variable DEBUG=1 to allow more verbose error output from Vim.
+#
+# See: http://vim.wikia.com/wiki/Vim_as_a_system_interpreter_for_vimscript
+
+export LD_LIBRARY_PATH=.
+vimscriptfile=${STEP:-stepA_mal}.vim
+if [ -n "${DEBUG:-}" ] ; then
+  exec 2> /dev/null
+fi
+exec vim -i NONE -V1 -nNesS $vimscriptfile -- "$@" | cat
diff --git a/impls/vimscript/run_vimscript.sh b/impls/vimscript/run_vimscript.sh
deleted file mode 100755
index cf263c8f7f..0000000000
--- a/impls/vimscript/run_vimscript.sh
+++ /dev/null
@@ -1,17 +0,0 @@
-#!/bin/sh
-
-# Run Vim in ex mode (-e) and run the given script ($1) on startup. Our scripts
-# end with 'qall!' which causes actual Vim UI to never start up.
-#
-# Set environment variable DEBUG=1 to allow more verbose error output from Vim.
-#
-# See: http://vim.wikia.com/wiki/Vim_as_a_system_interpreter_for_vimscript
-
-rundir=`dirname $0`
-export LD_LIBRARY_PATH=`readlink -f $rundir`
-vimscriptfile="$1"
-shift
-if [ x$DEBUG = x ] ; then
-  exec 2> /dev/null
-fi
-exec vim -i NONE -V1 -nNesS $vimscriptfile -- "$@" | cat
diff --git a/impls/wasm/run b/impls/wasm/run
index 7d4fed5185..5958c5be40 100755
--- a/impls/wasm/run
+++ b/impls/wasm/run
@@ -1,18 +1,18 @@
-#!/usr/bin/env bash
-STEP=${STEP:-stepA_mal}
-case "${wasm_MODE}" in
+#!/bin/sh
+set -Cefu
+case ${wasm_MODE:-js} in
 wasmtime)
-    exec wasmtime --dir=./ --dir=../ --dir=/ $(dirname $0)/${STEP:-stepA_mal}.wasm "${@}" ;;
+    exec wasmtime --dir=./ --dir=../ --dir=/ ${STEP:-stepA_mal}.wasm "$@" ;;
 wasmer)
-    exec wasmer run --dir=./ --dir=../ --dir=/ $(dirname $0)/${STEP:-stepA_mal}.wasm -- "${@}" ;;
+    exec wasmer run --dir=./ --dir=../ --dir=/ ${STEP:-stepA_mal}.wasm -- "$@" ;;
 warpy)
-    exec warpy --argv --memory-pages 256 $(dirname $0)/${STEP:-stepA_mal}.wasm "${@}" ;;
+    exec warpy --argv --memory-pages 256 ${STEP:-stepA_mal}.wasm "$@" ;;
 wax)
-    exec wax $(dirname $0)/${STEP:-stepA_mal}.wasm "${@}" ;;
+    exec wax ${STEP:-stepA_mal}.wasm "$@" ;;
 wace_libc)
-    exec wace $(dirname $0)/${STEP:-stepA_mal}.wasm "${@}" ;;
+    exec wace ${STEP:-stepA_mal}.wasm "$@" ;;
 wace_fooboot)
     echo >&2 "wace_fooboot mode not yet supported" ;;
 node|js|*)
-    exec ./run.js $(dirname $0)/${STEP:-stepA_mal}.wasm "${@}" ;;
+    exec node run.js ${STEP:-stepA_mal}.wasm "$@" ;;
 esac
diff --git a/impls/wasm/run.js b/impls/wasm/run.js
old mode 100755
new mode 100644
index 2deaa5e53c..59a705583d
--- a/impls/wasm/run.js
+++ b/impls/wasm/run.js
@@ -1,5 +1,3 @@
-#!/usr/bin/env node
-
 // Copyright Joel Martin
 // License MIT
 
@@ -128,7 +126,7 @@ async function loadWebAssembly(filename, args) {
 
 async function main() {
   assert(process.argv.length >= 3,
-         'Usage: ./run.js prog.wasm [ARGS...]')
+         'Usage: node run.js prog.wasm [ARGS...]')
 
   const wasm = process.argv[2]
   const args = process.argv.slice(2)
diff --git a/impls/wren/run b/impls/wren/run
index 8c269bf55a..5709bd1b38 100755
--- a/impls/wren/run
+++ b/impls/wren/run
@@ -1,2 +1,3 @@
-#!/usr/bin/env bash
-exec wren $(dirname $0)/${STEP:-stepA_mal}.wren "${@}"
+#!/bin/sh
+set -Cefu
+exec wren ${STEP:-stepA_mal}.wren "$@"
diff --git a/impls/yorick/run b/impls/yorick/run
index 78b865fca2..4431fca9b8 100755
--- a/impls/yorick/run
+++ b/impls/yorick/run
@@ -1,3 +1,3 @@
-#!/usr/bin/env bash
-export YORICK_MAL_PATH="$(dirname $0)"
-exec yorick -batch "$YORICK_MAL_PATH/${STEP:-stepA_mal}.i" "${@}"
+#!/bin/sh
+set -Cefu
+exec yorick -batch ${STEP:-stepA_mal}.i "$@"
diff --git a/impls/yorick/step1_read_print.i b/impls/yorick/step1_read_print.i
index 8a97cb8cf1..8d4bde5320 100644
--- a/impls/yorick/step1_read_print.i
+++ b/impls/yorick/step1_read_print.i
@@ -1,4 +1,3 @@
-set_path, get_env("YORICK_MAL_PATH") + ":" + get_path()
 require, "reader.i"
 require, "printer.i"
 
diff --git a/impls/yorick/step2_eval.i b/impls/yorick/step2_eval.i
index 40730a4967..984679c68b 100644
--- a/impls/yorick/step2_eval.i
+++ b/impls/yorick/step2_eval.i
@@ -1,4 +1,3 @@
-set_path, get_env("YORICK_MAL_PATH") + ":" + get_path()
 require, "reader.i"
 require, "printer.i"
 require, "core.i"
diff --git a/impls/yorick/step3_env.i b/impls/yorick/step3_env.i
index 604fb35a20..845ce2572d 100644
--- a/impls/yorick/step3_env.i
+++ b/impls/yorick/step3_env.i
@@ -1,4 +1,3 @@
-set_path, get_env("YORICK_MAL_PATH") + ":" + get_path()
 require, "reader.i"
 require, "printer.i"
 require, "core.i"
diff --git a/impls/yorick/step4_if_fn_do.i b/impls/yorick/step4_if_fn_do.i
index 6dac870716..a1bd63e183 100644
--- a/impls/yorick/step4_if_fn_do.i
+++ b/impls/yorick/step4_if_fn_do.i
@@ -1,4 +1,3 @@
-set_path, get_env("YORICK_MAL_PATH") + ":" + get_path()
 require, "reader.i"
 require, "printer.i"
 require, "core.i"
diff --git a/impls/yorick/step5_tco.i b/impls/yorick/step5_tco.i
index a9c8ffd96b..4f2011e7f7 100644
--- a/impls/yorick/step5_tco.i
+++ b/impls/yorick/step5_tco.i
@@ -1,4 +1,3 @@
-set_path, get_env("YORICK_MAL_PATH") + ":" + get_path()
 require, "reader.i"
 require, "printer.i"
 require, "core.i"
diff --git a/impls/yorick/step6_file.i b/impls/yorick/step6_file.i
index 9780f11926..843c08f024 100644
--- a/impls/yorick/step6_file.i
+++ b/impls/yorick/step6_file.i
@@ -1,4 +1,3 @@
-set_path, get_env("YORICK_MAL_PATH") + ":" + get_path()
 require, "reader.i"
 require, "printer.i"
 require, "core.i"
diff --git a/impls/yorick/step7_quote.i b/impls/yorick/step7_quote.i
index 4cd664ac38..c8eb843655 100644
--- a/impls/yorick/step7_quote.i
+++ b/impls/yorick/step7_quote.i
@@ -1,4 +1,3 @@
-set_path, get_env("YORICK_MAL_PATH") + ":" + get_path()
 require, "reader.i"
 require, "printer.i"
 require, "core.i"
diff --git a/impls/yorick/step8_macros.i b/impls/yorick/step8_macros.i
index 0060ecec7e..1ffcf9fe18 100644
--- a/impls/yorick/step8_macros.i
+++ b/impls/yorick/step8_macros.i
@@ -1,4 +1,3 @@
-set_path, get_env("YORICK_MAL_PATH") + ":" + get_path()
 require, "reader.i"
 require, "printer.i"
 require, "core.i"
diff --git a/impls/yorick/step9_try.i b/impls/yorick/step9_try.i
index 73df6647b9..f3e2308c9a 100644
--- a/impls/yorick/step9_try.i
+++ b/impls/yorick/step9_try.i
@@ -1,4 +1,3 @@
-set_path, get_env("YORICK_MAL_PATH") + ":" + get_path()
 require, "reader.i"
 require, "printer.i"
 require, "core.i"
diff --git a/impls/yorick/stepA_mal.i b/impls/yorick/stepA_mal.i
index 5251fafe8c..3205838d51 100644
--- a/impls/yorick/stepA_mal.i
+++ b/impls/yorick/stepA_mal.i
@@ -1,4 +1,3 @@
-set_path, get_env("YORICK_MAL_PATH") + ":" + get_path()
 require, "reader.i"
 require, "printer.i"
 require, "core.i"
diff --git a/impls/zig/run b/impls/zig/run
index 35613af46a..048ef39072 100755
--- a/impls/zig/run
+++ b/impls/zig/run
@@ -1,2 +1,3 @@
 #!/bin/sh
-exec $(dirname $0)/zig-out/bin/${STEP:-stepA_mal} "${@}"
+set -Cefu
+exec zig-out/bin/${STEP:-stepA_mal} "$@"
diff --git a/process/guide.md b/process/guide.md
index bda640206d..f8ec3f1c59 100644
--- a/process/guide.md
+++ b/process/guide.md
@@ -113,18 +113,31 @@ quux_STEP_TO_PROG = impls/quux/$($(1)).qx
   the "STEP" environment variable for the implementation step to run
   and defaults to "stepA_mal". Make sure the run script has the
   executable file permission set (or else the test runner might fail with a
-  permission denied error message). The following are examples of "run"
+  permission denied error message).
+
+  In order to disambiguate relative paths in command line arguments,
+  library search paths and so on, "run" will by convention always
+  executed in the implementation directory.
+
+```
+cd impls/quux
+./run ../tests/step0_repl.mal
+```
+
+  The following are examples of "run"
   scripts for a compiled language and an interpreted language (where
   the interpreter is named "quux"):
 
 ```
-#!/usr/bin/env bash
-exec $(dirname $0)/${STEP:-stepA_mal} "${@}"
+#!/bin/sh
+set -Cefu
+exec ./${STEP:-stepA_mal} "$@"
 ```
 
 ```
-#!/usr/bin/env bash
-exec quux $(dirname $0)/${STEP:-stepA_mal}.qx "${@}"
+#!/bin/sh
+set -Cefu
+exec quux ${STEP:-stepA_mal}.qx "$@"
 ```
 
 This allows you to run tests against your implementation like this: