make lint: Perform bash script linting

shell/update.sh

@@ -0,0 +1,67 @@
+#!/usr/bin/env bash
+
+# This script applies the contents of "common.sh" to the other files.
+
+set -e
+
+dir=${0%"${0##*/}"}
+
+update() {
+  {
+    sed -n '1,/^#----BEGIN INCLUDE common\.sh/p' "$1"
+    cat <<EOF
+# NOTE: Do not directly edit this section, which is copied from "common.sh".
+# To modify it, one can edit "common.sh" and run "./update.sh" to apply
+# the changes. See code comments in "common.sh" for the implementation details.
+EOF
+    grep -v '^[[:blank:]]*#' "$dir/common.sh" # remove code comments in common.sh
+    sed -n '/^#----END INCLUDE/,$p' "$1"
+  } > "$1.part"
+
+  mv -f "$1.part" "$1"
+}
+
+update "$dir/completion.bash"
+update "$dir/completion.zsh"
+update "$dir/key-bindings.bash"
+update "$dir/key-bindings.zsh"
+
+# Check if --check is in ARGV
+check=0
+rest=()
+for arg in "$@"; do
+  case $arg in
+    --check) check=1 ;;
+    *) rest+=("$arg") ;;
+  esac
+done
+
+fmt() {
+  if ! grep -q "^#----BEGIN shfmt" "$1"; then
+    if [[ $check == 1 ]]; then
+      shfmt -d "$1"
+      return $?
+    else
+      shfmt -w "$1"
+    fi
+  else
+    {
+      sed -n '1,/^#----BEGIN shfmt/p' "$1" | sed '$d'
+      sed -n '/^#----BEGIN shfmt/,/^#----END shfmt/p' "$1" | shfmt --filename "$1"
+      sed -n '/^#----END shfmt/,$p' "$1" | sed '1d'
+    } > "$1.part"
+
+    if [[ $check == 1 ]]; then
+      diff -q "$1" "$1.part"
+      ret=$?
+      rm -f "$1.part"
+      return $ret
+    fi
+
+    mv -f "$1.part" "$1"
+  fi
+}
+
+for file in "${rest[@]}"; do
+  fmt "$file" || exit $?
+done