diff --git a/.github/PULL_REQUEST_TEMPLATE.md b/.github/PULL_REQUEST_TEMPLATE.md
index 1dacb9c..2841b66 100644
--- a/.github/PULL_REQUEST_TEMPLATE.md
+++ b/.github/PULL_REQUEST_TEMPLATE.md
@@ -1,14 +1,15 @@
 ## Summary
 
-Description: 
+Description:
 
 - Tool repo URL:
-- Plugin repo URL: 
+- Plugin repo URL:
 
 ## Checklist
 
 - This PRs CI tests are green
-  - test locally with `./test_plugin.sh --file plugins/<PLUGIN_FILE>`
+  - format with `scripts/format.bash`
+  - test locally with `scripts/test_plugin.bash --file plugins/<your_new_plugin_name>`
 - [ ] Your plugin CI tests are green
   - _Tip: use the `plugin_test` action from [asdf-actions](https://github.com/asdf-vm/actions) in your plugin CI_
 
diff --git a/.github/workflows/format.yml b/.github/workflows/format.yml
deleted file mode 100644
index 1910fff..0000000
--- a/.github/workflows/format.yml
+++ /dev/null
@@ -1,30 +0,0 @@
-name: format
-
-on:
-  push:
-    branches:
-      - master
-    paths:
-      - README.md
-
-jobs:
-  format_readme:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@v3
-        with:
-          fetch-depth: 0
-
-      - name: Setup Node.js
-        uses: actions/setup-node@v3
-        with:
-          node-version: 18
-
-      - name: Format README.md
-        run: npx -y prettier --write README.md
-
-      - name: Commit format of README.md
-        uses: stefanzweifel/git-auto-commit-action@v4
-        with:
-          commit_message: "chore: format README.md"
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
new file mode 100644
index 0000000..aa4376f
--- /dev/null
+++ b/.github/workflows/lint.yml
@@ -0,0 +1,31 @@
+name: lint
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v3
+
+      - name: Install asdf dependencies
+        uses: asdf-vm/actions/install@v1
+
+      - name: lint
+        run: scripts/lint.bash
+
+  actionlint:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v3
+
+      - name: Check workflow files
+        uses: docker://rhysd/actionlint:1.6.23
+        with:
+          args: -color
diff --git a/.github/workflows/semantic-pr.yml b/.github/workflows/semantic-pr.yml
index eecb3d0..c135265 100644
--- a/.github/workflows/semantic-pr.yml
+++ b/.github/workflows/semantic-pr.yml
@@ -1,4 +1,4 @@
-name: lint pull request
+name: lint
 
 on:
   pull_request_target:
diff --git a/.github/workflows/test-all-plugins.yml b/.github/workflows/test-all-plugins.yml
new file mode 100644
index 0000000..0f2641b
--- /dev/null
+++ b/.github/workflows/test-all-plugins.yml
@@ -0,0 +1,21 @@
+name: test
+
+on:
+  push:
+    branches:
+      - master
+    paths:
+      - plugins/*
+      - README.md
+
+jobs:
+  all_plugins:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      - name: Check new plugin is registered correctly
+        run: bash scripts/test_plugin.bash --all
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 6f366c5..39b0d30 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -1,12 +1,12 @@
-name: Test
+name: test
 
 on:
   pull_request:
     paths:
-      - "plugins/*"
+      - plugins/*
 
 jobs:
-  check_plugin_registration:
+  changed_plugins:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
@@ -15,4 +15,4 @@ jobs:
           fetch-depth: 0
 
       - name: Check new plugin is registered correctly
-        run: bash test_plugin.sh --diff origin/master ${{ github.sha }}
+        run: bash scripts/test_plugin.bash --diff origin/master ${{ github.sha }}
diff --git a/.tool-versions b/.tool-versions
new file mode 100644
index 0000000..4826a78
--- /dev/null
+++ b/.tool-versions
@@ -0,0 +1,3 @@
+nodejs 18.14.0
+shellcheck 0.9.0
+shfmt 3.6.0
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 100644
index 0000000..41d5133
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,36 @@
+# Contributing
+
+## Contributing a new Plugin
+
+1. Clone this repo
+   ```bash
+   git clone https://github.com/asdf-vm/asdf-plugins
+   ```
+1. Install repo dependencies
+   ```bash
+   asdf install
+   ```
+1. Add the plugin to the repository `README.md` _Plugin List_ table.
+1. Create a file with the shortname you wish to be used by asdf in `plugins/<name>`. The contents should be `repository = <your_repo>`. Eg:
+   ```bash
+   printf "repository = https://github.com/asdf-vm/asdf-nodejs.git\n" > plugins/nodejs
+   ```
+1. Test your code
+   ```bash
+   scripts/test_plugin.bash --file plugins/<name>
+   ```
+1. Format your code & this README:
+   ```bash
+   scripts/format.bash
+   ```
+1. Create a PR following the instructions in the PR template.
+
+## Fixing an existing plugin
+
+If you see a plugin has an incorrect Build status link, please PR a fix to the correct link.
+
+If you see a plugin which is no longer maintained by the repository owner, please reach out to them on their repo before PRing a removal of the plugin. Sometimes code not actively maintained functions perfectly fine. If you PR a removal, link to the thread showing you attempted to communicate with the owner/author.
+
+---
+
+Thanks for contributing!
diff --git a/README.md b/README.md
index f923c26..7f398d4 100644
--- a/README.md
+++ b/README.md
@@ -27,8 +27,12 @@ If you're creating a new plugin consider creating it as part of the [`asdf-commu
 
 ## Contributing a new Plugin
 
-- Add the plugin to this `README.md`.
-- Create a file with the shortname you wish to be used by asdf in `plugins/<name>`. Then contents should be `repository = <your_repo>`.
+- Install repo dependencies: `asdf install`
+- Add the plugin to the repository `README.md` _Plugin List_ table.
+- Create a file with the shortname you wish to be used by asdf in `plugins/<name>`. The contents should be `repository = <your_repo>`.
+  - eg: `printf "repository = https://github.com/asdf-vm/asdf-nodejs.git\n" > plugins/nodejs`
+- Test your code : `scripts/test_plugin.bash --file plugins/<name>`
+- Format your code & this README: `scripts/format.bash`
 - Create a PR following the instructions in the PR template.
 
 ## Security
diff --git a/scripts/format.bash b/scripts/format.bash
new file mode 100755
index 0000000..3dc3ae7
--- /dev/null
+++ b/scripts/format.bash
@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+# format Shell scripts in scripts/ directory.
+shfmt --language-dialect bash --indent 2 --write \
+  ./scripts/*
+
+# format Markdown files.
+npx -y prettier --write \
+  ./**/*.md
diff --git a/scripts/lint.bash b/scripts/lint.bash
new file mode 100755
index 0000000..2cdcc48
--- /dev/null
+++ b/scripts/lint.bash
@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+# check format Shell scripts in scripts/ directory.
+shfmt --language-dialect bash --indent 2 --diff \
+  ./scripts/*
+
+# check format Markdown files.
+npx -y prettier --check \
+  ./**/*.md
+
+# lint for errors in Shell scripts in scripts/ directory.
+shellcheck --shell bash --external-sources \
+  ./scripts/*
diff --git a/test_plugin.sh b/scripts/test_plugin.bash
similarity index 81%
rename from test_plugin.sh
rename to scripts/test_plugin.bash
index d4f246c..acd38f6 100755
--- a/test_plugin.sh
+++ b/scripts/test_plugin.bash
@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 
-# See: ./test_plugin.sh --help
+# See: ./scripts/test_plugin.bash --help
 
 function fail() {
   echo "FAIL: $*" >&2
@@ -12,24 +12,25 @@ function badge_svg() {
   grep -o '(http[^)]*svg[^)]*)' | sed -e 's/(//;s/)//'
 }
 
-function check_plugin_from_diff() {
+function check_plugins_from_diff() {
   local BASE_REF="$1" # Base commit of main branch.
   local HEAD_REF="$2" # Latest commit of PR
 
   local DIFF_CHANGES
   DIFF_CHANGES="$(git diff --name-only "${BASE_REF}" "${HEAD_REF}")"
 
-  # Assert that the PR diff only includes a change to README and a file under plugins/
+  # Assert that the PR diff only includes a change to README and file(s) under plugins/ directory
   {
-    test "2" == "$(echo "$DIFF_CHANGES" | wc -l | xargs)" &&
+    test 1 -lt "$(echo "$DIFF_CHANGES" | wc --lines | xargs)" &&
       echo "$DIFF_CHANGES" | grep README.md >/dev/null &&
       echo "$DIFF_CHANGES" | grep plugins/ >/dev/null
   } || fail "Expected git diff ${REF_RANGE} to only include changes for a single plugin"
 
-  local PLUGIN_FILE
-  PLUGIN_FILE="$(git diff --name-only "${BASE_REF}" "${HEAD_REF}" -- plugins/)"
-
-  check_plugin_from_file "$PLUGIN_FILE"
+  local PLUGIN_FILES
+  PLUGIN_FILES="$(git diff --name-only "${BASE_REF}" "${HEAD_REF}" -- plugins/)"
+  for PLUGIN_FILE in $PLUGIN_FILES; do
+    check_plugin_from_file "$PLUGIN_FILE"
+  done
 }
 
 function check_plugin_from_file() {
@@ -41,7 +42,7 @@ function check_plugin_from_file() {
     fail "Expected a plugin file at $PLUGIN_FILE"
 
   # Assert that PLUGIN_FILE file ends with new line.
-  test 'X' == "$(tail -c1 "$PLUGIN_FILE" | tr '\n' 'X')" ||
+  test 'X' == "$(tail --bytes=1 "$PLUGIN_FILE" | tr '\n' 'X')" ||
     fail "Expected $PLUGIN_FILE to end with a new line."
 
   # Assert that PLUGIN_FILE has repository key and points to a git repo.
@@ -51,20 +52,20 @@ function check_plugin_from_file() {
     fail "File $PLUGIN_FILE does not specify a repository url"
 
   # Assert the plugin repo is reachable.
-  git ls-remote -q "$PLUGIN_REPO" HEAD >/dev/null ||
+  git ls-remote --quiet "$PLUGIN_REPO" HEAD >/dev/null ||
     fail "Repo is unreachable: $PLUGIN_REPO"
 
   local PLUGIN_REPO_NO_GIT
-  PLUGIN_REPO_NO_GIT="$(echo "$PLUGIN_REPO" | sed -e 's/\.git$//' | tr '/' '\n' | tail -n1)"
+  PLUGIN_REPO_NO_GIT="$(echo "$PLUGIN_REPO" | sed -e 's/\.git$//' | tr '/' '\n' | tail --lines 1)"
 
   local README_LINE
-  README_LINE="$(git grep -h -C0 "${PLUGIN_REPO_NO_GIT}" -- README.md | head -n 1)"
+  README_LINE="$(git grep -h --ignore-case -C0 "${PLUGIN_REPO_NO_GIT}" -- README.md | head --lines 1)"
 
   # Assert that a new line for plugin was added at README
   test -n "$README_LINE" ||
     fail "Expected a line at README.md with a link to ${PLUGIN_REPO_NO_GIT}"
 
-  BADGE_COLUMN="$(echo "${README_LINE}" | cut -d'|' -f4)"
+  BADGE_COLUMN="$(echo "${README_LINE}" | cut --delimiter='|' -f4)"
   BADGE_URL="$(echo "${BADGE_COLUMN}" | badge_svg)"
 
   # Assert that the badge has "pass" text in it, indicating the plugin is healthy
@@ -104,7 +105,7 @@ if test "--all" == "$*"; then
 
 elif test "--diff" == "$1"; then
   echo "Testing plugin introduced at git diff $2..$3"
-  check_plugin_from_diff "$2" "$3"
+  check_plugins_from_diff "$2" "$3"
 
 elif test "--file" == "$1"; then
   check_plugin_from_file "$2"