diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index f2268259f..aa5550cd6 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -49,9 +49,9 @@ jobs:
         sudo apt update
         sudo apt remove -y clang-6.0 libclang-common-6.0-dev libclang1-6.0 libllvm6.0
         sudo apt autoremove
-        sudo apt --no-install-recommends install -y clang-tools clang-format-6.0
-        clang-format-6.0 --version
+        sudo apt --no-install-recommends install -y clang-tools clang-format-6.0 shellcheck
         python3 -m pip install yapf==0.29.0
+        sudo snap install shfmt
     - name: Check
       run: |
         script/make-pretty check
diff --git a/script/make-pretty b/script/make-pretty
index c9ffae457..bb1c9179f 100755
--- a/script/make-pretty
+++ b/script/make-pretty
@@ -30,7 +30,7 @@
 #
 # The script to check or format source code of OpenThread.
 #
-# Format c/c++, markdown, and python:
+# Format c/c++, markdown, python, and shell:
 #
 #     script/make-pretty
 #
@@ -46,11 +46,16 @@
 #
 #     script/make-pretty python
 #
+# Format shell only:
+#
+#     script/make-pretty shell
+#
 # Check only:
 #
 #     script/make-pretty check clang
 #     script/make-pretty check markdown
 #     script/make-pretty check python
+#     script/make-pretty check shell
 #
 
 set -euo pipefail
@@ -62,102 +67,121 @@ readonly OT_CLANG_SOURCES=('*.c' '*.cc' '*.cpp' '*.h' '*.hpp')
 readonly OT_MARKDOWN_SOURCES=('*.md')
 readonly OT_PYTHON_SOURCES=('*.py')
 
-do_clang_format()
-{
+do_clang_format() {
     echo -e '====================='
     echo -e '     format c/c++'
     echo -e '====================='
 
-    git ls-files "${OT_CLANG_SOURCES[@]}" | grep -v -E "^($(echo "${OT_EXCLUDE_DIRS[@]}" | tr ' ' '|'))" \
-        | xargs -n3 -P"${OT_BUILD_JOBS}" script/clang-format -style=file -i -verbose
+    git ls-files "${OT_CLANG_SOURCES[@]}" | grep -v -E "^($(echo "${OT_EXCLUDE_DIRS[@]}" | tr ' ' '|'))" |
+        xargs -n3 -P"$OT_BUILD_JOBS" script/clang-format -style=file -i -verbose
 }
 
-do_clang_check()
-{
+do_clang_check() {
     echo -e '====================='
     echo -e '     check c/c++'
     echo -e '====================='
 
-    git ls-files "${OT_CLANG_SOURCES[@]}" | grep -v -E "^($(echo "${OT_EXCLUDE_DIRS[@]}" | tr ' ' '|'))" \
-        | xargs -n3 -P"${OT_BUILD_JOBS}" script/clang-format-check
+    git ls-files "${OT_CLANG_SOURCES[@]}" | grep -v -E "^($(echo "${OT_EXCLUDE_DIRS[@]}" | tr ' ' '|'))" |
+        xargs -n3 -P"$OT_BUILD_JOBS" script/clang-format-check
 }
 
-do_markdown_format()
-{
+do_markdown_format() {
     echo -e '======================'
     echo -e '     format markdown'
     echo -e '======================'
 
-    git ls-files "${OT_MARKDOWN_SOURCES[@]}" | grep -v -E "^($(echo "${OT_EXCLUDE_DIRS[@]}" | tr ' ' '|'))" \
-        | xargs -n10 -P"${OT_BUILD_JOBS}" npx prettier@2.0.4 --write
+    git ls-files "${OT_MARKDOWN_SOURCES[@]}" | grep -v -E "^($(echo "${OT_EXCLUDE_DIRS[@]}" | tr ' ' '|'))" |
+        xargs -n10 -P"$OT_BUILD_JOBS" npx prettier@2.0.4 --write
 }
 
-do_markdown_check()
-{
+do_markdown_check() {
     echo -e '======================'
     echo -e '     check markdown'
     echo -e '======================'
 
-    git ls-files "${OT_MARKDOWN_SOURCES[@]}" | grep -v -E "^($(echo "${OT_EXCLUDE_DIRS[@]}" | tr ' ' '|'))" \
-        | xargs -n10 -P"${OT_BUILD_JOBS}" npx prettier@2.0.4 --check
+    git ls-files "${OT_MARKDOWN_SOURCES[@]}" | grep -v -E "^($(echo "${OT_EXCLUDE_DIRS[@]}" | tr ' ' '|'))" |
+        xargs -n10 -P"$OT_BUILD_JOBS" npx prettier@2.0.4 --check
 }
 
-do_python_format()
-{
+do_python_format() {
     echo -e '======================'
     echo -e '     format python'
     echo -e '======================'
 
-    git ls-files "${OT_PYTHON_SOURCES[@]}" | grep -v -E "^($(echo "${OT_EXCLUDE_DIRS[@]}" | tr ' ' '|'))" \
-        | xargs -n10 -P"${OT_BUILD_JOBS}" python3 -m yapf --verbose --style google -ipr
+    git ls-files "${OT_PYTHON_SOURCES[@]}" | grep -v -E "^($(echo "${OT_EXCLUDE_DIRS[@]}" | tr ' ' '|'))" |
+        xargs -n10 -P"$OT_BUILD_JOBS" python3 -m yapf --verbose --style google -ipr
 }
 
-do_python_check()
-{
+do_python_check() {
     echo -e '====================='
     echo -e '     check python'
     echo -e '====================='
 
-    git ls-files "${OT_PYTHON_SOURCES[@]}" | grep -v -E "^($(echo "${OT_EXCLUDE_DIRS[@]}" | tr ' ' '|'))" \
-        | xargs -n10 -P"${OT_BUILD_JOBS}" python3 -m yapf --verbose --style google -dpr
+    git ls-files "${OT_PYTHON_SOURCES[@]}" | grep -v -E "^($(echo "${OT_EXCLUDE_DIRS[@]}" | tr ' ' '|'))" |
+        xargs -n10 -P"$OT_BUILD_JOBS" python3 -m yapf --verbose --style google -dpr
 }
 
-do_check()
-{
+do_shell_format() {
+    echo -e '====================='
+    echo -e '     format shell'
+    echo -e '====================='
+
+    shfmt -f . | grep -v -E "^($(echo "${OT_EXCLUDE_DIRS[@]}" | tr ' ' '|'))" |
+        xargs -n10 -P"$OT_BUILD_JOBS" shfmt -i 4 -bn -ci -fn -s -w
+}
+
+do_shell_check() {
+    echo -e '====================='
+    echo -e '     check shell'
+    echo -e '====================='
+
+    shfmt -f . | grep -v -E "^($(echo "${OT_EXCLUDE_DIRS[@]}" | tr ' ' '|'))" |
+        xargs -n10 -P"$OT_BUILD_JOBS" shfmt -i 4 -bn -ci -fn -s -d
+
+    shfmt -f . | grep -v -E "^($(echo "${OT_EXCLUDE_DIRS[@]}" | tr ' ' '|'))" |
+        xargs -n10 -P"$OT_BUILD_JOBS" shellcheck
+}
+
+do_check() {
     if [ $# == 0 ]; then
         do_clang_check
         do_markdown_check
         do_python_check
+        do_shell_check
     elif [ "$1" == 'clang' ]; then
         do_clang_check
     elif [ "$1" == 'markdown' ]; then
         do_markdown_check
     elif [ "$1" == 'python' ]; then
         do_python_check
+    elif [ "$1" == 'shell' ]; then
+        do_shell_check
     else
-        >&2 echo "Unsupported check: $1. Supported: clang, markdown, python"
+        echo >&2 "Unsupported check: $1. Supported: clang, markdown, python, shell"
         # 128 for Invalid arguments
         exit 128
     fi
 }
 
-main()
-{
+main() {
     if [ $# == 0 ]; then
         do_clang_format
         do_markdown_format
         do_python_format
+        do_shell_format
     elif [ "$1" == 'clang' ]; then
         do_clang_format
     elif [ "$1" == 'markdown' ]; then
         do_markdown_format
     elif [ "$1" == 'python' ]; then
         do_python_format
+    elif [ "$1" == 'shell' ]; then
+        do_shell_format
     elif [ "$1" == 'check' ]; then
         shift
         do_check "$@"
     else
-        >&2 echo "Unsupported action: $1. Supported: clang, markdown, python"
+        echo >&2 "Unsupported action: $1. Supported: clang, markdown, python, shell"
         # 128 for Invalid arguments
         exit 128
     fi