diff --git a/godownloader-misspell.sh b/godownloader-misspell.sh
index a353a33..8c8301e 100644
--- a/godownloader-misspell.sh
+++ b/godownloader-misspell.sh
@@ -28,7 +28,11 @@ but credits (and pull requests) appreciated.
 ------------------------------------------------------------------------
 EOF
 is_command() {
-  type $1 > /dev/null 2> /dev/null
+  command -v "$1" > /dev/null
+}
+uname_os() {
+  os=$(uname -s | tr '[:upper:]' '[:lower:]')
+  echo "$os"
 }
 uname_arch() {
   arch=$(uname -m)
@@ -40,16 +44,49 @@ uname_arch() {
   esac
   echo ${arch}
 }
-uname_os() {
-  os=$(uname -s | tr '[:upper:]' '[:lower:]')
-  echo ${os}
+uname_os_check() {
+  os=$(uname_os)
+  case "$os" in
+   darwin)    return 0 ;;
+   dragonfly) return 0 ;;
+   freebsd)   return 0 ;;
+   linux)     return 0 ;;
+   android)   return 0 ;;
+   nacl)      return 0 ;;
+   netbsd)    return 0 ;;
+   openbsd)   return 0 ;;
+   plan9)     return 0 ;;
+   solaris)   return 0 ;;
+   windows)   return 0 ;;
+  esac
+  echo "$0: uname_os_check: internal error '$(uname -s)' got converted to '$os' which is not a GOOS value. Please file bug at https://github.com/client9/posixshell"
+  return 1
+}
+uname_arch_check() {
+  arch=$(uname_arch)
+  case "$arch" in
+   386)      return 0 ;;
+   amd64)    return 0 ;;
+   arm64)    return 0 ;;
+   arm)      return 0 ;;
+   ppc64)    return 0 ;;
+   ppc64le)  return 0 ;;
+   mips)     return 0 ;;
+   mipsle)   return 0 ;;
+   mips64)   return 0 ;;
+   mips64le) return 0 ;;
+   s390x)    return 0 ;;
+   amd64p32) return 0 ;;
+  esac
+  echo "$0: uname_arch_check: internal error '$(uname -m)' got converted to '$arch' which is not a GOARCH value.  Please file bug report at https://github.com/client9/posixshell"
+  return 1
 }
 untar() {
   tarball=$1
-  case ${tarball} in
-  *.tar.gz|*.tgz) tar -xzf ${tarball} ;;
-  *.tar) tar -xf ${tarball} ;;
-  *.zip) unzip ${tarball} ;;
+  case "${tarball}" in
+  *.tar.gz|*.tgz) tar -xzf "${tarball}" ;;
+  *.tar) tar -xf "${tarball}" ;;
+  *.zip) unzip "${tarball}" ;;
   *)
     echo "Unknown archive format for ${tarball}"
     return 1
@@ -57,8 +94,8 @@ untar() {
 }
 mktmpdir() {
    test -z "$TMPDIR" && TMPDIR="$(mktemp -d)"
-   mkdir -p ${TMPDIR}
-   echo ${TMPDIR}
+   mkdir -p "${TMPDIR}"
+   echo "${TMPDIR}"
 }
 http_download() {
   local_file=$1
@@ -96,28 +133,27 @@ github_api() {
   http_download "$local_file" "$source_url" "$header"
 }
 github_last_release() {
-  OWNER_REPO=$1
-  VERSION=$(github_api - https://api.github.com/repos/${OWNER_REPO}/releases/latest | grep -m 1 "\"name\":" | cut -d ":" -f 2 | tr -d ' ",')
-  if [ -z "${VERSION}" ]; then
-    echo "Unable to determine latest release for ${OWNER_REPO}"
-    return 1
-  fi
-  echo ${VERSION}
+  owner_repo=$1
+  giturl="https://api.github.com/repos/${owner_repo}/releases/latest"
+  html=$(github_api - "$giturl")
+  version=$(echo "$html" | grep -m 1 "\"name\":" | cut -d ":" -f 2 | tr -d ' ",')
+  test -z "$version" && return 1
+  echo "$version"
 }
 hash_sha256() {
   TARGET=${1:-/dev/stdin};
   if is_command gsha256sum; then
-    hash=$(gsha256sum $TARGET) || return 1
-    echo $hash | cut -d ' ' -f 1
+    hash=$(gsha256sum "$TARGET") || return 1
+    echo "$hash" | cut -d ' ' -f 1
   elif is_command sha256sum; then
-    hash=$(sha256sum $TARGET) || return 1
-    echo $hash | cut -d ' ' -f 1
+    hash=$(sha256sum "$TARGET") || return 1
+    echo "$hash" | cut -d ' ' -f 1
   elif is_command shasum; then
-    hash=$(shasum -a 256 $TARGET 2>/dev/null) || return 1
-    echo $hash | cut -d ' ' -f 1
+    hash=$(shasum -a 256 "$TARGET" 2>/dev/null) || return 1
+    echo "$hash" | cut -d ' ' -f 1
   elif is_command openssl; then
-    hash=$(openssl -dst openssl dgst -sha256 $TARGET) || return 1
-    echo $hash | cut -d ' ' -f a
+    hash=$(openssl -dst openssl dgst -sha256 "$TARGET") || return 1
+    echo "$hash" | cut -d ' ' -f a
   else
     echo "hash_sha256: unable to find command to compute sha-256 hash"
     return 1
@@ -131,12 +167,12 @@ hash_sha256_verify() {
      return 1
   fi
   BASENAME=${TARGET##*/}
-  want=$(grep ${BASENAME} "${checksums}" 2> /dev/null | tr '\t' ' ' | cut -d ' ' -f 1)
+  want=$(grep "${BASENAME}" "${checksums}" 2> /dev/null | tr '\t' ' ' | cut -d ' ' -f 1)
   if [ -z "$want" ]; then
      echo "hash_sha256_verify: unable to find checksum for '${TARGET}' in '${checksums}'"
      return 1
   fi
-  got=$(hash_sha256 $TARGET)
+  got=$(hash_sha256 "$TARGET")
   if [ "$want" != "$got" ]; then
      echo "hash_sha256_verify: checksum for '$TARGET' did not verify ${want} vs $got"
      return 1
@@ -154,14 +190,24 @@ BINARY=misspell
 FORMAT=tar.gz
 BINDIR=${BINDIR:-./bin}
 
+uname_os_check
+uname_arch_check
+
 VERSION=$1
-if [ -z "${VERSION}" ]; then
-  usage $0
-  exit 1
-fi
+case "${VERSION}" in
+ latest)
+    VERSION=""
+    ;;
+ -h|-?|*help*)
+   usage "$0"
+   exit 1
+   ;;
+esac
+
+PREFIX="$OWNER/$REPO"
 
-if [ "${VERSION}" = "latest" ]; then
-  echo "Checking GitHub for latest version of ${OWNER}/${REPO}"
+if [ -z "${VERSION}" ]; then
+  echo "$PREFIX: checking GitHub for latest version"
   VERSION=$(github_last_release "$OWNER/$REPO")
 fi
 # if version starts with 'v', remove it
@@ -186,6 +232,8 @@ amd64) ARCH=64-bit ;;
 darwin) ARCH=macOS ;;
 esac
 
+echo "$PREFIX: found version ${VERSION} for ${OS}/${ARCH}"
+
 NAME=${BINARY}_${VERSION}_${OS}_${ARCH}
 TARBALL=${NAME}.${FORMAT}
 TARBALL_URL=https://github.com/${OWNER}/${REPO}/releases/download/v${VERSION}/${TARBALL}
@@ -198,14 +246,17 @@ CHECKSUM_URL=https://github.com/${OWNER}/${REPO}/releases/download/v${VERSION}/$
 # out preventing half-done work
 execute() {
   TMPDIR=$(mktmpdir)
-  http_download ${TMPDIR}/${TARBALL} ${TARBALL_URL}
+  echo "$PREFIX: downloading ${TARBALL_URL}"
+  http_download "${TMPDIR}/${TARBALL}" "${TARBALL_URL}"
 
-  http_download ${TMPDIR}/${CHECKSUM} ${CHECKSUM_URL}
-  hash_sha256_verify ${TMPDIR}/${TARBALL} ${TMPDIR}/${CHECKSUM}
+  echo "$PREFIX: verifying checksums"
+  http_download "${TMPDIR}/${CHECKSUM}" "${CHECKSUM_URL}"
+  hash_sha256_verify "${TMPDIR}/${TARBALL}" "${TMPDIR}/${CHECKSUM}"
 
-  (cd ${TMPDIR} && untar ${TARBALL})
-  install -d ${BINDIR}
-  install ${TMPDIR}/${BINARY} ${BINDIR}/
+  (cd "${TMPDIR}" && untar "${TARBALL}")
+  install -d "${BINDIR}"
+  install "${TMPDIR}/${BINARY}" "${BINDIR}/"
+  echo "$PREFIX: installed as ${BINDIR}/${BINARY}"
 }
 
 execute