Create updater.sh

thanks @overdodactyl !!

updater.sh

@@ -0,0 +1,44 @@
+#!/bin/bash
+
+### ghacks-user.js updater for Mac/Linux
+## author: @overdodactyl
+## version: 1.0
+
+ghacksjs="https://raw.githubusercontent.com/ghacksuserjs/ghacks-user.js/master/user.js"
+
+cd "`dirname $0`"
+
+echo -e "\nThis script should be run from your Firefox profile directory.\n"
+
+if [ -e user.js ]; then
+  echo "Your current user.js file for this profile will be backed up and the latest ghacks version from github will take its place."
+  echo -e "\nIf currently using the ghacks user.js, please compare versions:"
+  echo "  Available online: $(curl -s ${ghacksjs} | sed -n '4p')"
+  echo "  Currently using:  $(sed -n '4p' user.js)"
+else
+  echo "A user.js file does not exist in this profile. If you continue, the latest ghacks version from github will be downloaded."
+fi
+
+echo -e "\nIf a user-overrides.js file exists in this profile, it will be appended to the user.js.\n"
+
+read -p "Continue Y/N? " -n 1 -r
+echo -e "\n\n"
+
+if [[ $REPLY =~ ^[Yy]$ ]]; then
+  if [ -e user.js ]; then
+    # backup current user.js
+    bakfile="user.js.backup.$(date +"%Y-%m-%d_%H%M")"
+    mv user.js "${bakfile}" && echo "Your previous user.js file was backed up: ${bakfile}"
+  fi
+
+  # download latest ghacks user.js
+  echo "downloading latest ghacks user.js file"
+  curl -O ${ghacksjs} && echo "ghacks user.js has been downloaded"
+
+  if [ -e user-overrides.js ]; then
+    echo "user-overrides.js file found"
+    cat user-overrides.js >> user.js && echo "user-overrides.js has been appended to user.js"
+  fi
+else
+  echo "Process aborted"
+fi