diff --git a/bin/update.sh b/bin/update.sh
new file mode 100755
index 00000000..994be953
--- /dev/null
+++ b/bin/update.sh
@@ -0,0 +1,41 @@
+#!/usr/bin/env bash
+
+set -o errexit,nounset
+
+update() {
+    [[ -d $1 ]] || return
+
+    pushd "$1"
+    local L=$(git rev-parse @)
+    local R=$(git rev-parse @{u})
+    if [[ $L != $R ]]
+    then
+        echo "Updating $(basename $(pwd))"
+        shift
+        ${@:-git pull}
+    fi
+    popd
+}
+
+# Update OS
+case "$OSTYPE" in
+    darwin*)
+        brew update && brew upgrade && brew cleanup
+        ;;
+    linux*)
+        if command -v pacman >/dev/null; then
+            sudo pacman -Syu --noconfirm
+        elif command -v apt-get >/dev/null; then
+            sudo apt-get update && sudo apt-get upgrade -y
+        fi
+esac
+
+# Update editors
+update ~/.emacs.d "make update"
+update ~/.vim     "make update"
+
+# Others
+update ~/.zgen
+update ~/.cask
+update ~/.{rb,py}env
+