--- a/configure
+++ b/configure
@@ -1,10 +1,10 @@
-#!/bin/bash
+#!/bin/sh
 
 # set environment variables used by scripts/make.sh
 
 # People run ./configure out of habit, so do "defconfig" for them.
 
-if [ "$(basename "$0")" == configure ]
+if [ "$(basename "$0")" = configure ]
 then
   echo "Assuming you want 'make defconfig', but you should probably check the README."
   make defconfig
@@ -12,8 +12,12 @@
 fi
 
 # Warn about stuff, disable stupid warnings, be 8-bit clean for utf8.
-[ "${CFLAGS/-funsigned-char//}" == "$CFLAGS" ] &&
-  CFLAGS+=" -Wall -Wundef -Werror=implicit-function-declaration -Wno-char-subscripts -Wno-pointer-sign -funsigned-char"
+case " ${CFLAGS-} " in
+  *" -funsigned-char "*) ;;
+  *)
+    CFLAGS="${CFLAGS-} -Wall -Wundef -Werror=implicit-function-declaration -Wno-char-subscripts -Wno-pointer-sign -funsigned-char"
+    ;;
+esac
 
 # Set default values if variable not already set
 : ${CC:=cc} ${HOSTCC:=cc} ${GENDIR:=generated} ${KCONFIG_CONFIG:=.config}
--- a/scripts/portability.sh
+++ b/scripts/portability.sh
@@ -1,6 +1,6 @@
 # sourced to find alternate names for things
 
-source ./configure
+. ./configure
 
 if [ -z "$(command -v "$CROSS_COMPILE$CC")" ]
 then
@@ -8,15 +8,20 @@
   exit 1
 fi
 
-if [ -z "$SED" ]
+if [ -z "${SED:-}" ]
 then
-  [ ! -z "$(command -v gsed 2>/dev/null)" ] && SED=gsed || SED=sed
+  if command -v gsed >/dev/null 2>&1
+  then
+    SED=gsed
+  else
+    SED=sed
+  fi
 fi
 
 # Tell linker to do dead code elimination at function level
-if [ "$(uname)" == "Darwin" ]
+if [ "$(uname)" = "Darwin" ]
 then
-  CFLAGS+=" -Wno-deprecated-declarations"
+  CFLAGS="${CFLAGS} -Wno-deprecated-declarations"
   : ${LDOPTIMIZE:=-Wl,-dead_strip} ${STRIP:=strip}
 else
   : ${LDOPTIMIZE:=-Wl,--gc-sections -Wl,--as-needed} ${STRIP:=strip -s -R .note* -R .comment}
@@ -24,9 +29,9 @@
 
 # Disable pointless warnings only clang produces
 [ -n "$("$CROSS_COMPILE$CC" --version | grep -w clang)" ] &&
-  CFLAGS+=" -Wno-string-plus-int -Wno-invalid-source-encoding" ||
+  CFLAGS="${CFLAGS} -Wno-string-plus-int -Wno-invalid-source-encoding" ||
 # And ones only gcc produces
-  CFLAGS+=" -Wno-restrict -Wno-format-overflow"
+  CFLAGS="${CFLAGS} -Wno-restrict -Wno-format-overflow"
 
 # Address Sanitizer
 if [ -n "$ASAN" ]; then
@@ -55,9 +60,10 @@
 
 # Run a C file from scripts/*.c using $HOSTCC as necessary
 brun() {
-  [ ! -e "$UNSTRIPPED"/$1 -o "$UNSTRIPPED"/$1 -ot scripts/$1.c ] &&
+  tool=$1
+  shift
+  [ ! -e "$UNSTRIPPED"/$tool -o "$UNSTRIPPED"/$tool -ot scripts/$tool.c ] &&
     { mkdir -p "$UNSTRIPPED" &&
-      do_loudly $HOSTCC scripts/$1.c -o "$UNSTRIPPED"/$1 || exit 1; }
-  do_loudly "$UNSTRIPPED"/$1 "${@:2}"
+      do_loudly $HOSTCC scripts/$tool.c -o "$UNSTRIPPED"/$tool || exit 1; }
+  do_loudly "$UNSTRIPPED"/$tool "$@"
 }
-
--- a/scripts/genconfig.sh
+++ b/scripts/genconfig.sh
@@ -1,9 +1,9 @@
-#!/bin/bash
+#!/bin/sh
 
 # This has to be a separate file from scripts/make.sh so it can be called
 # before menuconfig. (It's called again from scripts/make.sh just to be sure.)
 
-source scripts/portability.sh
+. scripts/portability.sh
 
 mkdir -p "$GENDIR"
 
@@ -16,9 +16,11 @@
 # Symbol name is first argument, flags second, feed C file to stdin
 probesymbol()
 {
-  probecc "${@:2}" 2>/dev/null && DEFAULT=y || DEFAULT=n
+  symbol=$1
+  shift
+  probecc "$@" 2>/dev/null && DEFAULT=y || DEFAULT=n
   rm a.out 2>/dev/null
-  echo -e "config $1\n\tbool\n\tdefault $DEFAULT\n" || exit 1
+  printf 'config %s\n\tbool\n\tdefault %s\n\n' "$symbol" "$DEFAULT" || exit 1
 }
 
 probeconfig()
@@ -35,7 +37,7 @@
     #include <unistd.h>
     int main(int argc, char *argv[]) { return fork(); }
 EOF
-  echo -e '\tdepends on !TOYBOX_FORCE_NOMMU'
+  printf '\tdepends on !TOYBOX_FORCE_NOMMU\n'
 }
 
 genconfig()
@@ -77,20 +79,22 @@
 toys toys/*/*.c | (
 while IFS=":" read FILE NAME
 do
-  echo -e "test_$NAME:\n\tscripts/test.sh $NAME\n"
-  [ "$NAME" == help ] && continue
-  [ "$NAME" == install ] && continue
-  [ "$NAME" == sh ] && FILE="toys/*/*.c"
-  echo -e "$NAME: $FILE *.[ch] lib/*.[ch]\n\tscripts/single.sh $NAME\n"
-  [ "${FILE/example//}" != "$FILE" ] && EXAMPLE="$EXAMPLE $NAME" ||
-  [ "${FILE/pending//}" != "$FILE" ] && PENDING="$PENDING $NAME" ||
-    WORKING="$WORKING $NAME"
+  printf 'test_%s:\n\tscripts/test.sh %s\n\n' "$NAME" "$NAME"
+  [ "$NAME" = help ] && continue
+  [ "$NAME" = install ] && continue
+  [ "$NAME" = sh ] && FILE="toys/*/*.c"
+  printf '%s: %s *.[ch] lib/*.[ch]\n\tscripts/single.sh %s\n\n' "$NAME" "$FILE" "$NAME"
+  case $FILE in
+    *example*) EXAMPLE="$EXAMPLE $NAME" ;;
+    *pending*) PENDING="$PENDING $NAME" ;;
+    *) WORKING="$WORKING $NAME" ;;
+  esac
 done &&
-echo -e "clean::\n\t@rm -f $WORKING $PENDING" &&
-echo -e "list:\n\t@echo $(echo $WORKING | tr ' ' '\n' | sort | xargs)" &&
-echo -e "list_example:\n\t@echo $(echo $EXAMPLE | tr ' ' '\n' | sort | xargs)"&&
-echo -e "list_pending:\n\t@echo $(echo $PENDING | tr ' ' '\n' | sort | xargs)"&&
-echo -e ".PHONY: $WORKING $PENDING" | $SED 's/ \([^ ]\)/ test_\1/g'
+printf 'clean::\n\t@rm -f%s%s\n' "$WORKING" "$PENDING" &&
+printf 'list:\n\t@echo %s\n' "$(echo "$WORKING" | tr ' ' '\n' | sort | xargs)" &&
+printf 'list_example:\n\t@echo %s\n' "$(echo "$EXAMPLE" | tr ' ' '\n' | sort | xargs)" &&
+printf 'list_pending:\n\t@echo %s\n' "$(echo "$PENDING" | tr ' ' '\n' | sort | xargs)" &&
+printf '.PHONY:%s%s\n' "$WORKING" "$PENDING" | $SED 's/ \([^ ]\)/ test_\1/g'
 ) > .singlemake
 
 brun kconfig -h > "$GENDIR"/help.h || exit 1
--- a/scripts/make.sh
+++ b/scripts/make.sh
@@ -1,50 +1,16 @@
-#!/bin/bash
+#!/bin/sh
 
 # Grab default values for $CFLAGS and such.
-set -o pipefail
-source scripts/portability.sh
-
-# Shell functions called by the build
-
-DASHN=-n
-true & wait -n 2>/dev/null || { wait; unset DASHN; }
-ratelimit()
-{
-  if [ "$#" -eq 0 ]
-  then
-    [ -z "$DASHN" ] && PIDS="$PIDS$! "
-    [ $((++COUNT)) -lt $CPUS ] && return 0
-  fi
-  ((--COUNT))
-  if [ -n "$DASHN" ]
-  then
-    wait -n
-    DONE=$(($DONE+$?))
-  else
-    # MacOS uses an ancient version of bash which hasn't got "wait -n", and
-    # wait without arguments always returns 0 instead of process exit code.
-    # This keeps $CPUS less busy when jobs finish out of order.
-    wait ${PIDS%% *}
-    DONE=$(($DONE+$?))
-    PIDS=${PIDS#* }
-  fi
-
-  return $DONE
-}
-
-# Respond to V= by echoing command lines as well as running them
-do_loudly()
-{
-  { [ -n "$V" ] && echo "$@" || echo -n "$DOTPROG" ; } >&2
-  "$@"
-}
+. scripts/portability.sh
 
 # Is anything under directory $2 newer than generated/$1 (or does it not exist)?
 isnewer()
 {
-  [ -e "$GENDIR/$1" ] && [ -z "$(find "${@:2}" -newer "$GENDIR/$1")" ] &&
+  target=$1
+  shift
+  [ -e "$GENDIR/$target" ] && [ -z "$(find "$@" -newer "$GENDIR/$target")" ] &&
     return 1
-  echo -n "${DIDNEWER:-$GENDIR/{}$1"
+  printf '%s' "${DIDNEWER:-$GENDIR/{}}$target"
   DIDNEWER=,
 }
 
@@ -64,16 +30,18 @@
   [ -z "$V" ] && X=/dev/null || X=/dev/stderr
   for i in util crypt m resolv selinux smack attr crypto z log iconv tls ssl
   do
-    do_loudly ${CROSS_COMPILE}${CC} $CFLAGS $LDFLAGS -xc - -l$i >>$X 2>&1 \
-      -o /dev/null <<<"int main(int argc,char*argv[]){return 0;}" &&
-      echo -l$i &
+    printf '%s\n' 'int main(int argc,char*argv[]){return 0;}' |
+      do_loudly ${CROSS_COMPILE}${CC} $CFLAGS $LDFLAGS -xc - -l$i >>$X 2>&1 \
+      -o /dev/null && echo -l$i &
   done | sort | xargs
 )
 # Actually resolve dangling dependencies in extra libraries when static linking
-[ -n "$LIBRARIES" ] && [ "$LDFLAGS" != "${LDFLAGS/-static/}" ] &&
-  LIBRARIES="-Wl,--start-group $LIBRARIES -Wl,--end-group"
+[ -n "$LIBRARIES" ] &&
+case $LDFLAGS in
+  *-static*) LIBRARIES="-Wl,--start-group $LIBRARIES -Wl,--end-group" ;;
+esac
 
-[ -z "$VERSION" ] && [ -d ".git" ] && [ -n "$(which git 2>/dev/null)" ] &&
+[ -z "$VERSION" ] && [ -d ".git" ] && command -v git >/dev/null 2>&1 &&
   VERSION="$(git describe --tags --abbrev=12 2>/dev/null)"
 
 # Set/record build environment information
@@ -93,33 +61,42 @@
 
 # Make sure rm -rf isn't gonna go funny
 B="$(readlink -f "$PWD")/" A="$(readlink -f "$GENDIR")" A="${A%/}"/
-[ "$A" == "${B::${#A}}" ] &&
-  { echo "\$GENDIR=$GENDIR cannot include \$PWD=$PWD"; exit 1; }
+case $B in
+  "$A"*)
+    echo "\$GENDIR=$GENDIR cannot include \$PWD=$PWD"
+    exit 1
+    ;;
+esac
 unset A B DOTPROG DIDNEWER
 
 # Force full rebuild if our compiler/linker options changed
-cmp -s <(compflags | grep '#d') <(grep '%d' "$GENDIR"/build.sh 2>/dev/null) ||
-  rm -rf "$GENDIR"/* # Keep symlink, delete contents
+new_build=$(mktemp)
+old_build=$(mktemp)
+compflags | grep '#d' > "$new_build"
+grep '#d' "$GENDIR"/build.sh 2>/dev/null > "$old_build" || :
+cmp -s "$new_build" "$old_build" || rm -rf "$GENDIR"/* # Keep symlink, delete contents
+rm -f "$new_build" "$old_build"
 mkdir -p "$UNSTRIPPED"  "$(dirname $OUTNAME)" || exit 1
 
 # Extract a list of toys/*/*.c files to compile from the data in $KCONFIG_CONFIG
 # (First command names, then filenames with relevant {NEW,OLD}TOY() macro.)
 
-[ -n "$V" ] && echo -e "\nWhich C files to build..."
+[ -n "$V" ] && printf '\nWhich C files to build...\n'
 TOYFILES="$($SED -n 's/^CONFIG_\([^=]*\)=.*/\1/p' "$KCONFIG_CONFIG" | xargs | tr ' ' '|')"
 TOYFILES="main.c $(egrep -l "^USE_($TOYFILES)[(]...TOY[(]" toys/*/*.c | xargs)"
 
-if [ "${TOYFILES/pending//}" != "$TOYFILES" ]
-then
-  echo -e "\n\033[1;31mwarning: using unfinished code from toys/pending\033[0m"
-fi
+case $TOYFILES in
+  *pending*)
+    printf '\n\033[1;31mwarning: using unfinished code from toys/pending\033[0m\n'
+    ;;
+esac
 
 # Write build variables (and set them locally), then append build invocation.
-compflags > "$GENDIR"/build.sh && source "$GENDIR/build.sh" &&
+compflags > "$GENDIR"/build.sh && . "$GENDIR"/build.sh &&
   {
-    echo FILES=$'"\n'"$(fold -s <<<"$TOYFILES")"$'\n"' &&
+    printf 'FILES="\n%s\n"\n' "$(printf '%s\n' "$TOYFILES" | fold -s)" &&
     echo &&
-    echo -e "\$BUILD lib/*.c \$FILES \$LINK -o $OUTNAME"
+    printf '%s\n' "\$BUILD lib/*.c \$FILES \$LINK -o $OUTNAME"
   } >> "$GENDIR"/build.sh &&
   chmod +x "$GENDIR"/build.sh || exit 1
 
@@ -133,7 +110,7 @@
 B="$(egrep "^CONFIG_($(echo "$A" | sed 's/=[yn]//' | xargs | tr ' ' '|'))=" "$KCONFIG_CONFIG" | $SED 's/^CONFIG_//' | sort)"
 A="$(echo "$A" | grep -v =n)"
 [ "$A" != "$B" ] &&
-  { echo -e "\nWarning: Config.probed changed, run 'make oldconfig'" >&2; }
+  { printf "\nWarning: Config.probed changed, run 'make oldconfig'\n" >&2; }
 unset A B
 
 # Create a list of all the commands toybox can provide.
@@ -171,7 +148,7 @@
 
     echo "#define NEWTOY(aa,bb,cc) aa $I bb"
     echo '#define OLDTOY(...)'
-    if [ "$I" == A ]
+    if [ "$I" = A ]
     then
       cat "$GENDIR"/config.h
     else
@@ -207,8 +184,8 @@
   $TOYFILES)"
   echo "$STRUX" &&
   echo "extern union global_union {" &&
-  $SED -n 's/^struct \(.*\)_data .*/\1/;T;s/.*/\tstruct &_data &;/p' \
-    <<<"$STRUX" &&
+  printf '%s\n' "$STRUX" | \
+    $SED -n 's/^struct \(.*\)_data .*/\1/;T;s/.*/\tstruct &_data &;/p' &&
   echo "} this;"
 } > "$GENDIR"/globals.h || exit 1
 
@@ -220,8 +197,10 @@
   for j in $i; do
     [ $X -eq 31 ] && LL=LL
     NAME="$HEAD$j"
+    VALUE="(1$LL<<$X)"
     printf "#define $NAME %*s%s\n#define _$NAME %*s%s\n" \
-      $((32-${#NAME})) "" "$X" $((31-${#NAME})) "" "(1$LL<<$((X++)))" || exit 1
+      $((32-${#NAME})) "" "$X" $((31-${#NAME})) "" "$VALUE" || exit 1
+    X=$((X+1))
   done
 done > "$GENDIR"/tags.h || exit 1
 
@@ -240,7 +219,7 @@
   rm -f "$GENDIR"/zhelp.h
 fi
 
-[ -z "$DIDNEWER" ] || echo }
+[ -z "$DIDNEWER" ] || echo '}'
 [ -n "$NOBUILD" ] && exit 0
 
 echo "Compile $OUTNAME"
@@ -260,12 +239,16 @@
 
 # build each generated/obj/*.o file in parallel
 
-PENDING= LNKFILES= CLICK= DONE=0 COUNT=0
+LNKFILES=
+CLICK=
 for i in lib/*.c click $TOYFILES
 do
-  [ "$i" == click ] && CLICK=1 && continue
+  [ "$i" = click ] && CLICK=1 && continue
 
-  X=${i/lib\//lib_}
+  X=$i
+  case $X in
+    lib/*) X=lib_${X#lib/} ;;
+  esac
   X=${X##*/}
   OUT="$GENDIR/obj/${X%%.c}.o"
   LNKFILES="$LNKFILES $OUT"
@@ -274,19 +257,10 @@
   [ "$OUT" -nt "$i" ] && [ -z "$CLICK" -o "$OUT" -nt "$KCONFIG_CONFIG" ] &&
     continue
 
-  do_loudly $BUILD -c $i -o $OUT &
-
-  ratelimit || break
-done
-
-# wait for all background jobs, detecting errors
-while [ "$COUNT" -gt 0 ]
-do
-  ratelimit done
+  do_loudly $BUILD -c $i -o $OUT || exit 1
 done
-[ $DONE -ne 0 ] && exit 1
 
-UNSTRIPPED="$UNSTRIPPED/${OUTNAME/*\//}"
+UNSTRIPPED="$UNSTRIPPED/${OUTNAME##*/}"
 do_loudly $BUILD $LNKFILES $LINK -o "$UNSTRIPPED" || exit 1
 if [ -n "$NOSTRIP" ] ||
   ! do_loudly ${CROSS_COMPILE}${STRIP} "$UNSTRIPPED" -o "$OUTNAME"
--- a/scripts/install.sh
+++ b/scripts/install.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 
 # usage: PREFIX=/target/path scripts/install.sh [--options]
 
@@ -12,29 +12,29 @@
 
 # Grab default values for $CFLAGS and such (to build scripts/install.c)
 
-source scripts/portability.sh
+. scripts/portability.sh
 
 [ -z "$PREFIX" ] && PREFIX="$PWD/install"
 
 # Parse command line arguments.
 
 LONG_PATH=""
-while [ ! -z "$1" ]
+while [ -n "${1:-}" ]
 do
   # Create symlinks instead of hardlinks?
-  [ "$1" == "--symlink" ] && TYPE="-s"
+  [ "$1" = "--symlink" ] && TYPE="-s"
 
   # Uninstall?
-  [ "$1" == "--uninstall" ] && UNINSTALL=Uninstall
+  [ "$1" = "--uninstall" ] && UNINSTALL=Uninstall
 
   # Delete destination command if it exists?
-  [ "$1" == "--force" ] && FORCE="-f"
+  [ "$1" = "--force" ] && FORCE="-f"
 
   # Use {,usr}/{bin,sbin} paths instead of all files in one directory?
-  [ "$1" == "--long" ] && LONG_PATH="bin/"
+  [ "$1" = "--long" ] && LONG_PATH="bin/"
 
   # Symlink host toolchain binaries to destination to create cross compile $PATH
-  [ "$1" == "--airlock" ] && AIRLOCK=1
+  [ "$1" = "--airlock" ] && AIRLOCK=1
 
   shift
 done
@@ -52,7 +52,7 @@
 then
   mkdir -p "${PREFIX}/${LONG_PATH}" &&
   rm -f "${PREFIX}/${LONG_PATH}/toybox" &&
-  cp toybox"${TARGET:+-$TARGET}" ${PREFIX}/${LONG_PATH} || exit 1
+  cp toybox"${TARGET:+-$TARGET}" "${PREFIX}/${LONG_PATH}/" || exit 1
 else
   rm -f "${PREFIX}/${LONG_PATH}/toybox" 2>/dev/null
 fi
@@ -107,7 +107,7 @@
 # python and deciding to #include Python.h).
 
 # mkroot has patches to remove the need for "bc" and "gcc"
-TOOLCHAIN="${TOOLCHAIN//,/ } as cc ld objdump   bc gcc"
+TOOLCHAIN="$(printf '%s' "${TOOLCHAIN:-}" | tr ',' ' ') as cc ld objdump   bc gcc"
 
 # The following are commands toybox should provide, but doesn't yet.
 # For now symlink the host version. This list must go away by 1.0.
@@ -134,7 +134,7 @@
         ln -sf "$j" "$FALLBACK/$i" || exit 1
       fi
 
-      X=$[$X+1]
+      X=$((X+1))
       FALLBACK="$PREFIX/fallback-$X"
     done