diff --git a/.editorconfig b/.editorconfig
index 1923d41..8ce7973 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -1,7 +1,7 @@
 root = true
 
-[*]
-indent_style = space
+[bin/*]
+indent_style = tab
 indent_size = 2
 charset = utf-8
 trim_trailing_whitespace = true
diff --git a/README.md b/README.md
index 6c5fcb2..b499fe0 100644
--- a/README.md
+++ b/README.md
@@ -22,7 +22,7 @@
 
 # Install
 
-> asdf-janet will automatically install JPM from master branch. You disable JPM installation by setting environment variable `JPM_TAG` to empty string.
+> asdf-janet will automatically install JPM from master branch. You disable JPM installation by setting environment variable `JPM_REF` to space(`JPM_REF=""`).
 
 Plugin:
 
diff --git a/bin/download b/bin/download
index 80abb60..b47c82e 100755
--- a/bin/download
+++ b/bin/download
@@ -2,21 +2,25 @@
 
 set -euo pipefail
 
-current_script_path=${BASH_SOURCE[0]}
-plugin_dir=$(dirname "$(dirname "$current_script_path")")
-
-# shellcheck source=../lib/utils.bash
-source "${plugin_dir}/lib/utils.bash"
-
-mkdir -p "$ASDF_DOWNLOAD_PATH"
-
-release_file="$ASDF_DOWNLOAD_PATH/$TOOL_NAME-$ASDF_INSTALL_VERSION.tar.gz"
-
-# Download tar.gz file to the download directory
-download_release "$ASDF_INSTALL_VERSION" "$release_file"
-
-#  Extract contents of tar.gz file into the download directory
-tar -xzf "$release_file" -C "$ASDF_DOWNLOAD_PATH" --strip-components=1 || fail "Could not extract $release_file"
-
-# Remove the tar.gz file since we don't need to keep it
-rm "$release_file"
+declare \
+	janet_repo="https://github.com/janet-lang/janet" \
+	janet_version=$ASDF_INSTALL_VERSION \
+	jpm_repo="https://github.com/janet-lang/jpm"
+declare -a curl_opts=(-fsSL)
+
+if [ -n "${GITHUB_API_TOKEN:-}" ]; then
+	curl_opts=("${curl_opts[@]}" -H "Authorization: token $GITHUB_API_TOKEN")
+fi
+if [ "$ASDF_INSTALL_TYPE" = "version" ]; then
+	janet_version="v${janet_version}"
+fi
+if [ ! -d "${ASDF_DOWNLOAD_PATH}/janet" ]; then
+	mkdir -p "${ASDF_DOWNLOAD_PATH}/janet"
+	curl "${curl_opts[@]}" "${janet_repo}/archive/${janet_version}.tar.gz" |
+		tar -C "${ASDF_DOWNLOAD_PATH}/janet" --strip-components=1 -xzf -
+fi
+if [ "${JPM_REF:-"master"}" != " " ] && [ ! -d "${ASDF_DOWNLOAD_PATH}/jpm" ]; then
+	mkdir -p "${ASDF_DOWNLOAD_PATH}/jpm"
+	curl "${curl_opts[@]}" "${jpm_repo}/archive/${JPM_REF:-"master"}.tar.gz" |
+		tar -C "${ASDF_DOWNLOAD_PATH}/jpm" --strip-components=1 -xzf -
+fi
diff --git a/bin/exec-env b/bin/exec-env
new file mode 100755
index 0000000..f1ef286
--- /dev/null
+++ b/bin/exec-env
@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+if [ -v LD_LIBRARY_PATH ]; then
+	export LD_LIBRARY_PATH="${ASDF_INSTALL_PATH}/bin:${LD_LIBRARY_PATH}/lib"
+else
+	export LD_LIBRARY_PATH="${ASDF_INSTALL_PATH}/lib"
+fi
diff --git a/bin/install b/bin/install
index 9737a63..03bb437 100755
--- a/bin/install
+++ b/bin/install
@@ -2,10 +2,35 @@
 
 set -euo pipefail
 
-current_script_path=${BASH_SOURCE[0]}
-plugin_dir=$(dirname "$(dirname "$current_script_path")")
+declare git_hash
 
-# shellcheck source=../lib/utils.bash
-source "${plugin_dir}/lib/utils.bash"
+if [ "$ASDF_INSTALL_TYPE" = "version" ]; then
+	git_hash="meson"
+else
+	git_hash="$ASDF_INSTALL_VERSION"
+fi
 
-install_version "$ASDF_INSTALL_TYPE" "$ASDF_INSTALL_VERSION" "$ASDF_INSTALL_PATH"
+if [ -v LD_LIBRARY_PATH ]; then
+	export LD_LIBRARY_PATH="${ASDF_INSTALL_PATH}/bin:${LD_LIBRARY_PATH}/lib"
+else
+	export LD_LIBRARY_PATH="${ASDF_INSTALL_PATH}/lib"
+fi
+
+mkdir -p "$ASDF_INSTALL_PATH"
+pushd "${ASDF_DOWNLOAD_PATH}/janet" >/dev/null
+meson setup build \
+	--buildtype release \
+	--optimization 2 \
+	--prefix "$ASDF_INSTALL_PATH" \
+	--libdir "${ASDF_INSTALL_PATH}/lib" \
+	-Dgit_hash="$git_hash"
+ninja -C build -j "${ASDF_CONCURRENCY:-1}"
+ninja -C build install -j "${ASDF_CONCURRENCY:-1}"
+popd >/dev/null
+[ -x "${ASDF_INSTALL_PATH}/bin/janet" ]
+if [ "${JPM_REF:-"master"}" != " " ]; then
+	pushd "${ASDF_DOWNLOAD_PATH}/jpm" >/dev/null
+	PREFIX="$ASDF_INSTALL_PATH" "${ASDF_INSTALL_PATH}/bin/janet" bootstrap.janet
+	popd >/dev/null
+	[ -x "${ASDF_INSTALL_PATH}/bin/jpm" ]
+fi
diff --git a/bin/list-all b/bin/list-all
index 943371e..23fa2d2 100755
--- a/bin/list-all
+++ b/bin/list-all
@@ -2,10 +2,12 @@
 
 set -euo pipefail
 
-current_script_path=${BASH_SOURCE[0]}
-plugin_dir=$(dirname "$(dirname "$current_script_path")")
-
-# shellcheck source=../lib/utils.bash
-source "${plugin_dir}/lib/utils.bash"
-
-list_all_versions | sort_versions | xargs echo
+declare janet_repo="https://github.com/janet-lang/janet"
+git ls-remote --tags --refs "$janet_repo" |
+	grep -o 'refs/tags/.*' |
+	cut -d/ -f3- |
+	sed 's/^v//' |
+	sed 'h; s/[+-]/./g; s/.p\([[:digit:]]\)/.z\1/; s/$/.z/; G; s/\n/ /' |
+	LC_ALL=C sort -t. -k 1,1 -k 2,2n -k 3,3n -k 4,4n -k 5,5n |
+	awk '{print $2}' |
+	xargs printf "%s "
diff --git a/lib/utils.bash b/lib/utils.bash
deleted file mode 100644
index 0ca9c3d..0000000
--- a/lib/utils.bash
+++ /dev/null
@@ -1,94 +0,0 @@
-#!/usr/bin/env bash
-
-set -euo pipefail
-
-GH_REPO="https://github.com/janet-lang/janet"
-GH_REPO_JPM="https://github.com/janet-lang/jpm"
-TOOL_NAME="janet"
-TOOL_TEST="janet -v"
-JPM_TAG=${JPM_TAG:-master}
-
-fail() {
-  echo -e "asdf-$TOOL_NAME: $*"
-  exit 1
-}
-
-curl_opts=(-fsSL)
-
-# NOTE: You might want to remove this if janet is not hosted on GitHub releases.
-if [ -n "${GITHUB_API_TOKEN:-}" ]; then
-  curl_opts=("${curl_opts[@]}" -H "Authorization: token $GITHUB_API_TOKEN")
-fi
-
-sort_versions() {
-  sed 'h; s/[+-]/./g; s/.p\([[:digit:]]\)/.z\1/; s/$/.z/; G; s/\n/ /' |
-    LC_ALL=C sort -t. -k 1,1 -k 2,2n -k 3,3n -k 4,4n -k 5,5n | awk '{print $2}'
-}
-
-list_github_tags() {
-  git ls-remote --tags --refs "$GH_REPO" |
-    grep -o 'refs/tags/.*' | cut -d/ -f3- |
-    sed 's/^v//' # NOTE: You might want to adapt this sed to remove non-version strings from tags
-}
-
-list_all_versions() {
-  list_github_tags
-}
-
-download_release() {
-  local version filename url
-  version="$1"
-  filename="$2"
-  if [ "$ASDF_INSTALL_TYPE" = "version" ]; then
-    version="v${version}"
-  fi
-
-  url="$GH_REPO/archive/${version}.tar.gz"
-
-  echo "* Downloading $TOOL_NAME $version..."
-  curl "${curl_opts[@]}" -o "$filename" -C - "$url" || fail "Could not download $url"
-}
-
-install_version() {
-  local install_type="$1"
-  local version="$2"
-  local install_path="$3"
-  local tool_cmd
-  tool_cmd="${install_path}/bin/$(echo "$TOOL_TEST" | cut -d' ' -f1)"
-  local git_hash
-  if [ "$ASDF_INSTALL_TYPE" = "version" ]; then
-    git_hash="meson"
-  else
-    git_hash="$ASDF_INSTALL_VERSION"
-  fi
-
-  (
-    mkdir -p "$install_path"
-    pushd "$ASDF_DOWNLOAD_PATH"
-    meson setup build \
-      --buildtype release \
-      --optimization 2 \
-      --prefix "$install_path" \
-      --libdir "${install_path}/lib" \
-      -Dgit_hash="$git_hash"
-    ninja -C build
-    ninja -C build install
-    if [ -n "$JPM_TAG" ]; then
-      local jpm_url="${GH_REPO_JPM}/archive/${JPM_TAG}.tar.gz"
-      mkdir "${ASDF_DOWNLOAD_PATH}/jpm"
-      curl "${curl_opts[@]}" "$jpm_url" | tar -C "${ASDF_DOWNLOAD_PATH}/jpm" -xzf - --strip-components=1 ||
-        fail "Could not extract JPM archive"
-      pushd "${ASDF_DOWNLOAD_PATH}/jpm"
-      PREFIX="$install_path" "$tool_cmd" bootstrap.janet
-      popd
-    fi
-    popd
-
-    test -x "$tool_cmd" || fail "Expected $tool_cmd to be executable."
-
-    echo "$TOOL_NAME $version installation was successful!"
-  ) || (
-    rm -rf "$install_path"
-    fail "An error ocurred while installing $TOOL_NAME $version."
-  )
-}
diff --git a/scripts/shellcheck.bash b/scripts/shellcheck.bash
index 6d28a72..7e35d19 100755
--- a/scripts/shellcheck.bash
+++ b/scripts/shellcheck.bash
@@ -1,4 +1,4 @@
 #!/usr/bin/env bash
 
 exec shellcheck -s bash -x \
-  bin/* -P lib/
+	bin/* -P lib/