diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 00000000..15230cdb
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,20 @@
+root = true
+
+[*.{sh,bash}]
+indent_style       = space
+indent_size        = 2
+simplify           = true
+binary_next_line   = true
+switch_case_indent = true
+space_redirects    = true
+function_next_line = false
+
+# also bash scripts.
+[{install,uninstall,bin/fzf-preview.sh,bin/fzf-tmux}]
+indent_style       = space
+indent_size        = 2
+simplify           = true
+binary_next_line   = true
+switch_case_indent = true
+space_redirects    = true
+function_next_line = false
diff --git a/.github/workflows/linux.yml b/.github/workflows/linux.yml
index 2c5ee36d..454f56e9 100644
--- a/.github/workflows/linux.yml
+++ b/.github/workflows/linux.yml
@@ -33,7 +33,7 @@ jobs:
         ruby-version: 3.4.1
 
     - name: Install packages
-      run: sudo apt-get install --yes zsh fish tmux
+      run: sudo apt-get install --yes zsh fish tmux shfmt
 
     - name: Install Ruby gems
       run: bundle install
diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
index 79596a1a..69e98e86 100644
--- a/.github/workflows/macos.yml
+++ b/.github/workflows/macos.yml
@@ -30,7 +30,7 @@ jobs:
         ruby-version: 3.0.0
 
     - name: Install packages
-      run: HOMEBREW_NO_INSTALL_CLEANUP=1 brew install fish zsh tmux
+      run: HOMEBREW_NO_INSTALL_CLEANUP=1 brew install fish zsh tmux shfmt
 
     - name: Install Ruby gems
       run: gem install --no-document minitest:5.14.2 rubocop:1.0.0 rubocop-minitest:0.10.1 rubocop-performance:1.8.1
diff --git a/Makefile b/Makefile
index d66d2ef8..efd1aeb6 100644
--- a/Makefile
+++ b/Makefile
@@ -5,6 +5,15 @@ MAKEFILE       := $(realpath $(lastword $(MAKEFILE_LIST)))
 ROOT_DIR       := $(shell dirname $(MAKEFILE))
 SOURCES        := $(wildcard *.go src/*.go src/*/*.go shell/*sh man/man1/*.1) $(MAKEFILE)
 
+BASH_SCRIPTS   := $(ROOT_DIR)/bin/fzf-preview.sh \
+					$(ROOT_DIR)/bin/fzf-tmux \
+					$(ROOT_DIR)/install \
+					$(ROOT_DIR)/uninstall \
+					$(ROOT_DIR)/shell/common.sh \
+					$(ROOT_DIR)/shell/update-common.sh
+BASH_SCRIPTS_INDENT_LEFT	:= $(ROOT_DIR)/shell/completion.bash \
+								$(ROOT_DIR)/shell/key-bindings.bash
+
 ifdef FZF_VERSION
 VERSION        := $(FZF_VERSION)
 else
@@ -88,9 +97,20 @@ itest:
 bench:
 	cd src && SHELL=/bin/sh GOOS= $(GO) test -v -tags "$(TAGS)" -run=Bench -bench=. -benchmem
 
-lint: $(SOURCES) test/*.rb test/lib/*.rb
+lint: $(SOURCES) test/*.rb test/lib/*.rb ${BASH_SCRIPTS}
 	[ -z "$$(gofmt -s -d src)" ] || (gofmt -s -d src; exit 1)
 	bundle exec rubocop -a --require rubocop-minitest --require rubocop-performance
+	[ -z "$$(shfmt -d $(BASH_SCRIPTS))" ] || (echo "format bash files by (make fmt)"; exit 1)
+
+fmt: $(SOURCES) $(BASH_SCRIPTS) $(BASH_SCRIPTS_INDENT_LEFT)
+	gofmt -s -w src
+	shfmt -w $(BASH_SCRIPTS)
+	# shift left because we have an outermost if block for historical reasons.
+	for f in $(BASH_SCRIPTS_INDENT_LEFT); do \
+		shfmt -w "$$f"; \
+		tmp=$$(mktemp); \
+		sed 's/^  //' "$$f" > "$$tmp" && mv "$$tmp" "$$f"; \
+	done
 
 install: bin/fzf
 
@@ -189,4 +209,4 @@ update:
 	$(GO) get -u
 	$(GO) mod tidy
 
-.PHONY: all generate build release test itest bench lint install clean docker docker-test update
+.PHONY: all generate build release test itest bench lint install clean docker docker-test update fmt