diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index ccc65901..6727f4c3 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -6,61 +6,26 @@ on:
       - master
   pull_request:
 
+env:
+  PYTHON_MIN_VERSION: "3.7.13"
+
 jobs:
-  shellcheck:
+  asdf:
     runs-on: ubuntu-latest
     steps:
-      - name: Checkout code
-        uses: actions/checkout@v3
-
-      - name: Install asdf dependencies
-        uses: asdf-vm/actions/install@v2
-
-      - name: Run ShellCheck
-        run: scripts/shellcheck.bash
-
-  shellfmt:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@v3
-
-      - name: Install Fish (for fish_indent)
-        run: |
-          sudo add-apt-repository -y ppa:fish-shell/nightly-master
-          sudo apt-get update
-          sudo apt-get -y install fish
-
-      - name: Install asdf dependencies
-        uses: asdf-vm/actions/install@v2
-
-      - name: List file to shfmt
-        run: shfmt -f .
-
-      - name: Run shfmt
-        run: scripts/shfmt.bash
-
-  checkstyle-py:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@v3
-
-      - name: Install Python
-        uses: actions/setup-python@v4
+      - uses: actions/checkout@v3
+      - uses: asdf-vm/actions/install@v2
+      - uses: actions/setup-python@v4
         with:
-          python-version: "3.7.13"
+          python-version: ${{ env.PYTHON_MIN_VERSION }}
+      - run: scripts/install_dependencies.bash
+      - run: scripts/lint.bash --check
 
-      - name: Run checkstyle.py
-        run: scripts/checkstyle.py
-
-  actionlint:
+  actions:
     runs-on: ubuntu-latest
     steps:
-      - name: Checkout code
-        uses: actions/checkout@v3
-
+      - uses: actions/checkout@v3
       - name: Check workflow files
-        uses: docker://rhysd/actionlint:1.6.23
+        uses: docker://rhysd/actionlint:1.6.24
         with:
           args: -color
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index d45730b6..ec5931d5 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -6,12 +6,6 @@ on:
       - master
   pull_request:
 
-env:
-  ELVISH_VERSION: v0.19.2
-  FISH_VERSION: 3.6.1
-  NUSHELL_VERSION: 0.78.0
-  POWERSHELL_VERSION: 7.3.3
-
 jobs:
   detect-changes:
     runs-on: ubuntu-latest
@@ -22,11 +16,9 @@ jobs:
       documentation: ${{ steps.filter.outputs.documentation }}
       cli: ${{ steps.filter.outputs.cli }}
     steps:
-      - name: Checkout code
-        uses: actions/checkout@v3
+      - uses: actions/checkout@v3
         with:
           fetch-depth: 0
-
       - uses: dorny/paths-filter@v2
         id: filter
         with:
@@ -34,7 +26,6 @@ jobs:
             documentation:
               - '.github/workflows/**'
               - 'docs/**'
-              - '.tool-versions'
             cli:
               - '.github/workflows/**'
               - 'bin/**'
@@ -42,10 +33,9 @@ jobs:
               - 'scripts/**'
               - 'test/**'
               - '.tool-versions'
-              - 'asdf.elv'
-              - 'asdf.fish'
-              - 'asdf.nu'
-              - 'asdf.sh'
+              - 'asdf.*'
+              - 'defaults'
+              - 'help.txt'
 
   ubuntu:
     needs: detect-changes
@@ -54,46 +44,11 @@ jobs:
     if: ${{ needs.detect-changes.outputs.cli == 'true' }}
     runs-on: ubuntu-latest
     steps:
-      - name: Checkout code
-        uses: actions/checkout@v3
+      - uses: actions/checkout@v3
         with:
           fetch-depth: 0
-
-      - name: Install test dependencies
-        run: |
-          curl -fsSLo- https://packages.microsoft.com/keys/microsoft.asc | sudo tee >/dev/null /etc/apt/trusted.gpg.d/microsoft.asc
-          sudo sh -c 'echo "deb [arch=amd64] https://packages.microsoft.com/repos/microsoft-debian-bullseye-prod bullseye main" > /etc/apt/sources.list.d/microsoft.list'
-          sudo add-apt-repository -y ppa:fish-shell/release-3
-          sudo apt-get update
-          sudo apt-get -y install curl parallel \
-            fish="${{ env.FISH_VERSION }}-1~jammy" \
-            powershell="${{ env.POWERSHELL_VERSION }}-1.deb"
-
-          # Create $HOME/bin
-          mkdir -p "$HOME/bin"
-
-          # Download elvish binary and add to path
-          curl https://dl.elv.sh/linux-amd64/elvish-${{ env.ELVISH_VERSION }}.tar.gz -o elvish-${{ env.ELVISH_VERSION }}.tar.gz
-          tar xzf elvish-${{ env.ELVISH_VERSION }}.tar.gz
-          rm elvish-${{ env.ELVISH_VERSION }}.tar.gz
-          mv elvish-${{ env.ELVISH_VERSION }} "$HOME/bin/elvish"
-
-          # Download nushell binary and add to path
-          curl -L https://github.com/nushell/nushell/releases/download/${{ env.NUSHELL_VERSION }}/nu-${{ env.NUSHELL_VERSION }}-x86_64-unknown-linux-gnu.tar.gz -o nu-${{ env.NUSHELL_VERSION }}-x86_64-unknown-linux-gnu.tar.gz
-          tar xzf nu-${{ env.NUSHELL_VERSION }}-x86_64-unknown-linux-gnu.tar.gz
-          rm nu-${{ env.NUSHELL_VERSION }}-x86_64-unknown-linux-gnu.tar.gz
-          mv nu-${{ env.NUSHELL_VERSION }}-x86_64-unknown-linux-gnu/* "$HOME/bin"
-
-          # Add $HOME/bin to path
-          echo "$HOME/bin" >>"$GITHUB_PATH"
-
-      - name: Install bats
-        run: |
-          git clone --depth 1 --branch "v$(grep -Eo "^\\s*bats\\s*.*$" ".tool-versions" | cut -d ' ' -f2-)" https://github.com/bats-core/bats-core.git "$HOME/bats-core"
-          echo "$HOME/bats-core/bin" >>"$GITHUB_PATH"
-
-      - name: Run tests
-        run: scripts/test.bash
+      - run: scripts/install_dependencies.bash
+      - run: scripts/test.bash
         env:
           GITHUB_API_TOKEN: ${{ github.token }}
 
@@ -104,26 +59,11 @@ jobs:
     if: ${{ needs.detect-changes.outputs.cli == 'true' }}
     runs-on: macos-latest
     steps:
-      - name: Checkout code
-        uses: actions/checkout@v3
+      - uses: actions/checkout@v3
         with:
           fetch-depth: 0
-
-      - name: Install test dependencies
-        run: |
-          brew install coreutils parallel \
-            elvish \
-            fish \
-            nushell \
-            powershell
-
-      - name: Install bats
-        run: |
-          git clone --depth 1 --branch "v$(grep -Eo "^\\s*bats\\s*.*$" ".tool-versions" | cut -d ' ' -f2-)" https://github.com/bats-core/bats-core.git "$HOME/bats-core"
-          echo "$HOME/bats-core/bin" >>"$GITHUB_PATH"
-
-      - name: Run tests
-        run: scripts/test.bash
+      - run: scripts/install_dependencies.bash
+      - run: scripts/test.bash
         env:
           GITHUB_API_TOKEN: ${{ github.token }}
 
@@ -141,13 +81,11 @@ jobs:
           fetch-depth: 0
 
       # only run steps past here if changes to docs/** directory
-      - name: Setup Node.js
-        uses: actions/setup-node@v3
+      - uses: actions/setup-node@v3
         with:
           node-version: "18"
 
-      - name: Cache dependencies
-        uses: actions/cache@v3
+      - uses: actions/cache@v3
         id: npm-cache
         with:
           path: |
diff --git a/docs/contribute/core.md b/docs/contribute/core.md
index 76201e2d..046f195f 100644
--- a/docs/contribute/core.md
+++ b/docs/contribute/core.md
@@ -40,14 +40,15 @@ If you want to try out your changes without making change to your installed `asd
 It is best to format, lint and test your code locally before you commit or push to the remote. Use the following scripts/commands:
 
 ```shell:no-line-numbers
-# Shellcheck
-./scripts/shellcheck.bash
+# Lint
+./scripts/lint.bash --check
 
-# Format
-./scripts/shfmt.bash
+# Fix & Format
+./scripts/lint.bash --fix
 
 # Test: all tests
-bats test/
+./scripts/test.bash
+
 # Test: for specific command
 bats test/list_commands.bash
 ```
diff --git a/scripts/format.bash b/scripts/format.bash
deleted file mode 100755
index f8d4385b..00000000
--- a/scripts/format.bash
+++ /dev/null
@@ -1,24 +0,0 @@
-#!/usr/bin/env bash
-
-set -euo pipefail
-
-# check .bash files
-shfmt --language-dialect bash --indent 2 --write \
-  completions/*.bash \
-  bin/asdf \
-  bin/private/asdf-exec \
-  lib/utils.bash \
-  lib/commands/*.bash \
-  lib/functions/*.bash \
-  scripts/*.bash \
-  test/test_helpers.bash \
-  test/fixtures/dummy_broken_plugin/bin/* \
-  test/fixtures/dummy_legacy_plugin/bin/* \
-  test/fixtures/dummy_plugin/bin/*
-
-# check .bats files
-shfmt --language-dialect bats --indent 2 --write \
-  test/*.bats
-
-# check .fish files
-fish_indent --write ./**/*.fish
diff --git a/scripts/install_dependencies.bash b/scripts/install_dependencies.bash
new file mode 100755
index 00000000..f8c6ecf5
--- /dev/null
+++ b/scripts/install_dependencies.bash
@@ -0,0 +1,77 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+IFS=$'\n\t'
+
+### Used env vars set by default in GitHub Actions
+# docs: https://docs.github.com/en/actions/learn-github-actions/variables#default-environment-variables
+# GITHUB_ACTIONS
+# RUNNER_OS
+
+if [ -z "$GITHUB_ACTIONS" ]; then
+  printf "%s\n" "GITHUB_ACTIONS is not set. This script is only intended to be run in GitHub Actions. Exiting."
+  exit 1
+fi
+
+if [ -z "$RUNNER_OS" ]; then
+  printf "%s\n" "RUNNER_OS is not set. This script is only intended to be run in GitHub Actions. Exiting."
+  exit 1
+fi
+
+### Set environment variables for tracking versions
+# Elvish
+elvish_semver="v0.19.2"
+# Fish
+fish_semver="3.6.1"
+fish_apt_semver="${fish_semver}-1~jammy"
+# Nushell
+nushell_semver="0.78.0"
+# Powershell
+powershell_semver="7.3.3"
+powershell_apt_semver="${powershell_semver}-1.deb"
+
+### Install dependencies on Linux
+if [ "$RUNNER_OS" = "Linux" ]; then
+  printf "%s\n" "Installing dependencies on Linux"
+
+  curl -fsSLo- https://packages.microsoft.com/keys/microsoft.asc | sudo tee /etc/apt/trusted.gpg.d/microsoft.asc >/dev/null
+  sudo sh -c 'echo "deb [arch=amd64] https://packages.microsoft.com/repos/microsoft-debian-bullseye-prod bullseye main" > /etc/apt/sources.list.d/microsoft.list'
+  sudo add-apt-repository -y ppa:fish-shell/release-3
+  sudo apt-get update
+  sudo apt-get -y install curl parallel \
+    fish="${fish_apt_semver}" \
+    powershell="${powershell_apt_semver}"
+
+  # Create $HOME/bin
+  mkdir -p "$HOME/bin"
+
+  # Download elvish binary and add to path
+  curl https://dl.elv.sh/linux-amd64/elvish-${elvish_semver}.tar.gz -o elvish-${elvish_semver}.tar.gz
+  tar xzf elvish-${elvish_semver}.tar.gz
+  rm elvish-${elvish_semver}.tar.gz
+  mv elvish-${elvish_semver} "$HOME/bin/elvish"
+
+  # Download nushell binary and add to path
+  curl -L https://github.com/nushell/nushell/releases/download/${nushell_semver}/nu-${nushell_semver}-x86_64-unknown-linux-gnu.tar.gz -o nu-${nushell_semver}-x86_64-unknown-linux-gnu.tar.gz
+  tar xzf nu-${nushell_semver}-x86_64-unknown-linux-gnu.tar.gz
+  rm nu-${nushell_semver}-x86_64-unknown-linux-gnu.tar.gz
+  mv nu-${nushell_semver}-x86_64-unknown-linux-gnu/* "$HOME/bin"
+
+  # Add $HOME/bin to path (add Elvish & Nushell to path)
+  echo "$HOME/bin" >>"$GITHUB_PATH"
+fi
+
+### Install dependencies on macOS
+if [ "$RUNNER_OS" = "macOS" ]; then
+  printf "%s\n" "Installing dependencies on macOS"
+  brew install coreutils parallel \
+    elvish \
+    fish \
+    nushell \
+    powershell
+fi
+
+### Install bats-core
+printf "%s\n" "Installing bats-core"
+git clone --depth 1 --branch "v$(grep -Eo "^\\s*bats\\s*.*$" ".tool-versions" | cut -d ' ' -f2-)" https://github.com/bats-core/bats-core.git "$HOME/bats-core"
+echo "$HOME/bats-core/bin" >>"$GITHUB_PATH"
diff --git a/scripts/lint.bash b/scripts/lint.bash
new file mode 100755
index 00000000..392d36b6
--- /dev/null
+++ b/scripts/lint.bash
@@ -0,0 +1,180 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+IFS=$'\n\t'
+
+usage() {
+  printf "%s\n" "Lint script for the asdf codebase. Must be executed from the"
+  printf "%s\n\n" "repository root directory."
+  printf "%s\n\n" "Usage: scripts/lint.bash [options]"
+  printf "%s\n" "Options:"
+  printf "%s\n" "  -c, --check   Error if any issues are found"
+  printf "%s\n" "  -f, --fix     Automatically fix issues if possible"
+  printf "%s\n" "  -h, --help    Display this help message"
+}
+
+run_shfmt_stylecheck() {
+  local shfmt_flag=""
+  if [ "$1" = "fix" ]; then
+    shfmt_flag="--write"
+  else
+    shfmt_flag="--diff"
+  fi
+
+  printf "%s\n" "[INFO] Checking .bash with shfmt"
+  shfmt --language-dialect bash --indent 2 "${shfmt_flag}" \
+    completions/*.bash \
+    bin/asdf \
+    bin/private/asdf-exec \
+    lib/utils.bash \
+    lib/commands/*.bash \
+    lib/functions/*.bash \
+    scripts/*.bash \
+    test/test_helpers.bash \
+    test/fixtures/dummy_broken_plugin/bin/* \
+    test/fixtures/dummy_legacy_plugin/bin/* \
+    test/fixtures/dummy_plugin/bin/*
+
+  printf "%s\n" "[INFO] Checking .bats with shfmt"
+  shfmt --language-dialect bats --indent 2 "${shfmt_flag}" \
+    test/*.bats
+}
+
+run_shellcheck_linter() {
+  printf "%s\n" "[INFO] Checking .sh files with Shellcheck"
+  shellcheck --shell sh --external-sources \
+    asdf.sh
+
+  printf "%s\n" "[INFO] Checking .bash files with Shellcheck"
+  shellcheck --shell bash --external-sources \
+    completions/*.bash \
+    bin/asdf \
+    bin/private/asdf-exec \
+    lib/utils.bash \
+    lib/commands/*.bash \
+    lib/functions/*.bash \
+    scripts/*.bash \
+    test/test_helpers.bash \
+    test/fixtures/dummy_broken_plugin/bin/* \
+    test/fixtures/dummy_legacy_plugin/bin/* \
+    test/fixtures/dummy_plugin/bin/*
+
+  printf "%s\n" "[INFO] Checking .bats files with Shellcheck"
+  shellcheck --shell bats --external-source \
+    test/*.bats
+}
+
+run_custom_python_stylecheck() {
+  local github_actions=${GITHUB_ACTIONS:-}
+  local flag=
+
+  if [ "$1" = "fix" ]; then
+    flag="--fix"
+  fi
+
+  if [ -n "$github_actions" ] && ! command -v python3 &>/dev/null; then
+    # fail if CI and no python3
+    printf "%s\n" "[ERROR] Detected execution in GitHub Actions but python3 was not found. This is required during CI linting."
+    exit 1
+  fi
+
+  if ! command -v python3 &>/dev/null; then
+    # skip if local and no python3
+    printf "%s\n" "[WARNING] python3 not found. Skipping Custom Python Script."
+  else
+    printf "%s\n" "[INFO] Checking files with Custom Python Script."
+    "${0%/*}/checkstyle.py" "${flag}"
+  fi
+
+}
+
+# TODO: there is no elvish linter/formatter yet
+#       see https://github.com/elves/elvish/issues/1651
+#run_elvish_linter() {
+#  printf "%s\n" "[WARNING] elvish linter/formatter not found, skipping for now."
+#}
+
+run_fish_linter() {
+  local github_actions=${GITHUB_ACTIONS:-}
+  local flag=
+
+  if [ "$1" = "fix" ]; then
+    flag="--write"
+  else
+    flag="--check"
+  fi
+
+  if [ -n "$github_actions" ] && ! command -v fish_indent &>/dev/null; then
+    # fail if CI and no fish_ident
+    printf "%s\n" "[ERROR] Detected execution in GitHub Actions but fish_indent was not found. This is required during CI linting."
+    exit 1
+  fi
+
+  if ! command -v fish_indent &>/dev/null; then
+    # skip if local and no fish_ident
+    printf "%s\n" "[WARNING] fish_indent not found. Skipping .fish files."
+  else
+    printf "%s\n" "[INFO] Checking .fish files with fish_indent"
+    fish_indent "${flag}" ./**/*.fish
+  fi
+}
+
+# TODO: there is no nushell linter/formatter yet
+#run_nushell_linter() {
+#  printf "%s\n" "[WARNING] nushell linter/formatter not found, skipping for now."
+#}
+
+# TODO: select powershell linter/formatter & setup installation in CI
+#run_powershell_linter() {
+#  printf "%s\n" "[WARNING] powershell linter/formatter not found, skipping for now."
+#}
+
+repo_root=$(git rev-parse --show-toplevel)
+if [ "$repo_root" != "$PWD" ]; then
+  printf "%s\n" "[ERROR] This scripts requires execution from the repository root directory."
+  printf "\t%s\t%s\n" "Repo root dir:" "$repo_root"
+  printf "\t%s\t%s\n\n" "Current dir:" "$PWD"
+  printf "%s\n" "See usage details with -h or --help."
+  exit 1
+fi
+
+if [ $# -eq 0 ]; then
+  printf "%s\n" "[ERROR] At least one option required."
+  printf "=%.0s" {1..60}
+  printf "\n"
+  usage
+  exit 1
+fi
+
+mode=
+case "$1" in
+-h | --help)
+  usage
+  exit 0
+  ;;
+-c | --check)
+  mode="check"
+  ;;
+-f | --fix)
+  mode="fix"
+  ;;
+*)
+  printf "%s\n" "[ERROR] Invalid flag: $1"
+  printf "=%.0s" {1..60}
+  printf "\n"
+  usage
+  exit 1
+  ;;
+esac
+
+printf "%s\"%s\"\n" "[INFO] Executing with mode: " "$mode"
+
+run_shfmt_stylecheck "$mode"
+run_custom_python_stylecheck "$mode"
+run_shellcheck_linter "$mode"
+run_fish_linter "$mode"
+#run_elvish_linter "$mode"
+#run_nushell_linter "$mode"
+#run_powershell_linter "$mode"
+
+printf "%s\n" "[INFO] Success!"
diff --git a/scripts/shellcheck.bash b/scripts/shellcheck.bash
deleted file mode 100755
index 7b56f745..00000000
--- a/scripts/shellcheck.bash
+++ /dev/null
@@ -1,24 +0,0 @@
-#!/usr/bin/env bash
-
-set -euo pipefail
-
-# check .sh files
-shellcheck --shell sh --external-sources \
-  asdf.sh
-
-# check .bash files
-shellcheck --shell bash --external-sources \
-  completions/*.bash \
-  bin/asdf \
-  bin/private/asdf-exec \
-  lib/utils.bash \
-  lib/commands/*.bash \
-  lib/functions/*.bash \
-  scripts/*.bash \
-  test/test_helpers.bash \
-  test/fixtures/dummy_broken_plugin/bin/* \
-  test/fixtures/dummy_legacy_plugin/bin/* \
-  test/fixtures/dummy_plugin/bin/*
-
-shellcheck --shell bats --external-source \
-  test/*.bats
diff --git a/scripts/shfmt.bash b/scripts/shfmt.bash
deleted file mode 100755
index d42ae205..00000000
--- a/scripts/shfmt.bash
+++ /dev/null
@@ -1,24 +0,0 @@
-#!/usr/bin/env bash
-
-set -euo pipefail
-
-# check .bash files
-shfmt --language-dialect bash --indent 2 --diff \
-  completions/*.bash \
-  bin/asdf \
-  bin/private/asdf-exec \
-  lib/utils.bash \
-  lib/commands/*.bash \
-  lib/functions/*.bash \
-  scripts/*.bash \
-  test/test_helpers.bash \
-  test/fixtures/dummy_broken_plugin/bin/* \
-  test/fixtures/dummy_legacy_plugin/bin/* \
-  test/fixtures/dummy_plugin/bin/*
-
-# check .bats files
-shfmt --language-dialect bats --indent 2 --diff \
-  test/*.bats
-
-# check .fish files
-fish_indent --check ./**/*.fish
diff --git a/scripts/test.bash b/scripts/test.bash
index 5e361fdd..13148590 100755
--- a/scripts/test.bash
+++ b/scripts/test.bash
@@ -1,6 +1,15 @@
 #!/usr/bin/env bash
 
 set -euo pipefail
+IFS=$'\n\t'
+
+repo_root=$(git rev-parse --show-toplevel)
+if [ "$repo_root" != "$PWD" ]; then
+  printf "%s\n" "[ERROR] This scripts requires execution from the repository root directory."
+  printf "\t%s\t%s\n" "Repo root dir:" "$repo_root"
+  printf "\t%s\t%s\n\n" "Current dir:" "$PWD"
+  exit 1
+fi
 
 test_directory="test"
 bats_options=(--timing --print-output-on-failure)